Some formats require a read-only :term:`bytes-like object`, and set a
pointer instead of a buffer structure. They work by checking that
-the object's :c:member:`PyBufferProcs.bf_releasebuffer` field is *NULL*,
+the object's :c:member:`PyBufferProcs.bf_releasebuffer` field is ``NULL``,
which disallows mutable objects such as :class:`bytearray`.
.. note::
``z`` (:class:`str` or ``None``) [const char \*]
Like ``s``, but the Python object may also be ``None``, in which case the C
- pointer is set to *NULL*.
+ pointer is set to ``NULL``.
``z*`` (:class:`str`, :term:`bytes-like object` or ``None``) [Py_buffer]
Like ``s*``, but the Python object may also be ``None``, in which case the
- ``buf`` member of the :c:type:`Py_buffer` structure is set to *NULL*.
+ ``buf`` member of the :c:type:`Py_buffer` structure is set to ``NULL``.
``z#`` (:class:`str`, read-only :term:`bytes-like object` or ``None``) [const char \*, int]
Like ``s#``, but the Python object may also be ``None``, in which case the C
- pointer is set to *NULL*.
+ pointer is set to ``NULL``.
``y`` (read-only :term:`bytes-like object`) [const char \*]
This format converts a bytes-like object to a C pointer to a character
``Z`` (:class:`str` or ``None``) [const Py_UNICODE \*]
Like ``u``, but the Python object may also be ``None``, in which case the
- :c:type:`Py_UNICODE` pointer is set to *NULL*.
+ :c:type:`Py_UNICODE` pointer is set to ``NULL``.
.. deprecated-removed:: 3.3 4.0
Part of the old-style :c:type:`Py_UNICODE` API; please migrate to using
``Z#`` (:class:`str` or ``None``) [const Py_UNICODE \*, int]
Like ``u#``, but the Python object may also be ``None``, in which case the
- :c:type:`Py_UNICODE` pointer is set to *NULL*.
+ :c:type:`Py_UNICODE` pointer is set to ``NULL``.
.. deprecated-removed:: 3.3 4.0
Part of the old-style :c:type:`Py_UNICODE` API; please migrate to using
This format requires two arguments. The first is only used as input, and
must be a :c:type:`const char\*` which points to the name of an encoding as a
- NUL-terminated string, or *NULL*, in which case ``'utf-8'`` encoding is used.
+ NUL-terminated string, or ``NULL``, in which case ``'utf-8'`` encoding is used.
An exception is raised if the named encoding is not known to Python. The
second argument must be a :c:type:`char\*\*`; the value of the pointer it
references will be set to a buffer with the contents of the argument text.
It requires three arguments. The first is only used as input, and must be a
:c:type:`const char\*` which points to the name of an encoding as a
- NUL-terminated string, or *NULL*, in which case ``'utf-8'`` encoding is used.
+ NUL-terminated string, or ``NULL``, in which case ``'utf-8'`` encoding is used.
An exception is raised if the named encoding is not known to Python. The
second argument must be a :c:type:`char\*\*`; the value of the pointer it
references will be set to a buffer with the contents of the argument text.
There are two modes of operation:
- If *\*buffer* points a *NULL* pointer, the function will allocate a buffer of
+ If *\*buffer* points a ``NULL`` pointer, the function will allocate a buffer of
the needed size, copy the encoded data into this buffer and set *\*buffer* to
reference the newly allocated storage. The caller is responsible for calling
:c:func:`PyMem_Free` to free the allocated buffer after usage.
- If *\*buffer* points to a non-*NULL* pointer (an already allocated buffer),
+ If *\*buffer* points to a non-``NULL`` pointer (an already allocated buffer),
:c:func:`PyArg_ParseTuple` will use this location as the buffer and interpret the
initial value of *\*buffer_length* as the buffer size. It will then copy the
encoded data into the buffer and NUL-terminate it. If the buffer is not large
``O`` (object) [PyObject \*]
Store a Python object (without any conversion) in a C object pointer. The C
program thus receives the actual object that was passed. The object's reference
- count is not increased. The pointer stored is not *NULL*.
+ count is not increased. The pointer stored is not ``NULL``.
``O!`` (object) [*typeobject*, PyObject \*]
Store a Python object in a C object pointer. This is similar to ``O``, but
Parse the parameters of a function that takes both positional and keyword
parameters into local variables. The *keywords* argument is a
- *NULL*-terminated array of keyword parameter names. Empty names denote
+ ``NULL``-terminated array of keyword parameter names. Empty names denote
:ref:`positional-only parameters <positional-only_parameter>`.
Returns true on success; on failure, it returns false and raises the
appropriate exception.
Create a new value based on a format string similar to those accepted by the
:c:func:`PyArg_Parse\*` family of functions and a sequence of values. Returns
- the value or *NULL* in the case of an error; an exception will be raised if
- *NULL* is returned.
+ the value or ``NULL`` in the case of an error; an exception will be raised if
+ ``NULL`` is returned.
:c:func:`Py_BuildValue` does not always build a tuple. It builds a tuple only if
its format string contains two or more format units. If the format string is
``s`` (:class:`str` or ``None``) [const char \*]
Convert a null-terminated C string to a Python :class:`str` object using ``'utf-8'``
- encoding. If the C string pointer is *NULL*, ``None`` is used.
+ encoding. If the C string pointer is ``NULL``, ``None`` is used.
``s#`` (:class:`str` or ``None``) [const char \*, int]
Convert a C string and its length to a Python :class:`str` object using ``'utf-8'``
- encoding. If the C string pointer is *NULL*, the length is ignored and
+ encoding. If the C string pointer is ``NULL``, the length is ignored and
``None`` is returned.
``y`` (:class:`bytes`) [const char \*]
This converts a C string to a Python :class:`bytes` object. If the C
- string pointer is *NULL*, ``None`` is returned.
+ string pointer is ``NULL``, ``None`` is returned.
``y#`` (:class:`bytes`) [const char \*, int]
This converts a C string and its lengths to a Python object. If the C
- string pointer is *NULL*, ``None`` is returned.
+ string pointer is ``NULL``, ``None`` is returned.
``z`` (:class:`str` or ``None``) [const char \*]
Same as ``s``.
``u`` (:class:`str`) [const wchar_t \*]
Convert a null-terminated :c:type:`wchar_t` buffer of Unicode (UTF-16 or UCS-4)
- data to a Python Unicode object. If the Unicode buffer pointer is *NULL*,
+ data to a Python Unicode object. If the Unicode buffer pointer is ``NULL``,
``None`` is returned.
``u#`` (:class:`str`) [const wchar_t \*, int]
Convert a Unicode (UTF-16 or UCS-4) data buffer and its length to a Python
- Unicode object. If the Unicode buffer pointer is *NULL*, the length is ignored
+ Unicode object. If the Unicode buffer pointer is ``NULL``, the length is ignored
and ``None`` is returned.
``U`` (:class:`str` or ``None``) [const char \*]
``O`` (object) [PyObject \*]
Pass a Python object untouched (except for its reference count, which is
- incremented by one). If the object passed in is a *NULL* pointer, it is assumed
+ incremented by one). If the object passed in is a ``NULL`` pointer, it is assumed
that this was caused because the call producing the argument found an error and
- set an exception. Therefore, :c:func:`Py_BuildValue` will return *NULL* but won't
+ set an exception. Therefore, :c:func:`Py_BuildValue` will return ``NULL`` but won't
raise an exception. If no exception has been raised yet, :exc:`SystemError` is
set.
``O&`` (object) [*converter*, *anything*]
Convert *anything* to a Python object through a *converter* function. The
function is called with *anything* (which should be compatible with :c:type:`void
- \*`) as its argument and should return a "new" Python object, or *NULL* if an
+ \*`) as its argument and should return a "new" Python object, or ``NULL`` if an
error occurred.
``(items)`` (:class:`tuple`) [*matching-items*]
respectively.
If there is an error in the format string, the :exc:`SystemError` exception is
- set and *NULL* returned.
+ set and ``NULL`` returned.
.. c:function:: PyObject* Py_VaBuildValue(const char *format, va_list vargs)
.. c:member:: void \*obj
A new reference to the exporting object. The reference is owned by
- the consumer and automatically decremented and set to *NULL* by
+ the consumer and automatically decremented and set to ``NULL`` by
:c:func:`PyBuffer_Release`. The field is the equivalent of the return
value of any standard C-API function.
As a special case, for *temporary* buffers that are wrapped by
:c:func:`PyMemoryView_FromBuffer` or :c:func:`PyBuffer_FillInfo`
- this field is *NULL*. In general, exporting objects MUST NOT
+ this field is ``NULL``. In general, exporting objects MUST NOT
use this scheme.
.. c:member:: Py_ssize_t len
Important exception: If a consumer requests a buffer without the
:c:macro:`PyBUF_FORMAT` flag, :c:member:`~Py_buffer.format` will
- be set to *NULL*, but :c:member:`~Py_buffer.itemsize` still has
+ be set to ``NULL``, but :c:member:`~Py_buffer.itemsize` still has
the value for the original format.
If :c:member:`~Py_buffer.shape` is present, the equality
``product(shape) * itemsize == len`` still holds and the consumer
can use :c:member:`~Py_buffer.itemsize` to navigate the buffer.
- If :c:member:`~Py_buffer.shape` is *NULL* as a result of a :c:macro:`PyBUF_SIMPLE`
+ If :c:member:`~Py_buffer.shape` is ``NULL`` as a result of a :c:macro:`PyBUF_SIMPLE`
or a :c:macro:`PyBUF_WRITABLE` request, the consumer must disregard
:c:member:`~Py_buffer.itemsize` and assume ``itemsize == 1``.
.. c:member:: const char \*format
A *NUL* terminated string in :mod:`struct` module style syntax describing
- the contents of a single item. If this is *NULL*, ``"B"`` (unsigned bytes)
+ the contents of a single item. If this is ``NULL``, ``"B"`` (unsigned bytes)
is assumed.
This field is controlled by the :c:macro:`PyBUF_FORMAT` flag.
The number of dimensions the memory represents as an n-dimensional array.
If it is ``0``, :c:member:`~Py_buffer.buf` points to a single item representing
a scalar. In this case, :c:member:`~Py_buffer.shape`, :c:member:`~Py_buffer.strides`
- and :c:member:`~Py_buffer.suboffsets` MUST be *NULL*.
+ and :c:member:`~Py_buffer.suboffsets` MUST be ``NULL``.
The macro :c:macro:`PyBUF_MAX_NDIM` limits the maximum number of dimensions
to 64. Exporters MUST respect this limit, consumers of multi-dimensional
.. c:macro:: PyBUF_FORMAT
Controls the :c:member:`~Py_buffer.format` field. If set, this field MUST
- be filled in correctly. Otherwise, this field MUST be *NULL*.
+ be filled in correctly. Otherwise, this field MUST be ``NULL``.
:c:macro:`PyBUF_WRITABLE` can be \|'d to any of the flags in the next section.
If ``ndim == 0``, the memory location pointed to by :c:member:`~Py_buffer.buf` is
interpreted as a scalar of size :c:member:`~Py_buffer.itemsize`. In that case,
-both :c:member:`~Py_buffer.shape` and :c:member:`~Py_buffer.strides` are *NULL*.
+both :c:member:`~Py_buffer.shape` and :c:member:`~Py_buffer.strides` are ``NULL``.
-If :c:member:`~Py_buffer.strides` is *NULL*, the array is interpreted as
+If :c:member:`~Py_buffer.strides` is ``NULL``, the array is interpreted as
a standard n-dimensional C-array. Otherwise, the consumer must access an
n-dimensional array as follows:
Send a request to *exporter* to fill in *view* as specified by *flags*.
If the exporter cannot provide a buffer of the exact type, it MUST raise
- :c:data:`PyExc_BufferError`, set :c:member:`view->obj` to *NULL* and
+ :c:data:`PyExc_BufferError`, set :c:member:`view->obj` to ``NULL`` and
return ``-1``.
On success, fill in *view*, set :c:member:`view->obj` to a new reference
On success, set :c:member:`view->obj` to a new reference to *exporter* and
return 0. Otherwise, raise :c:data:`PyExc_BufferError`, set
- :c:member:`view->obj` to *NULL* and return ``-1``;
+ :c:member:`view->obj` to ``NULL`` and return ``-1``;
If this function is used as part of a :ref:`getbufferproc <buffer-structs>`,
*exporter* MUST be set to the exporting object and *flags* must be passed
.. c:function:: PyObject* PyByteArray_FromStringAndSize(const char *string, Py_ssize_t len)
Create a new bytearray object from *string* and its length, *len*. On
- failure, *NULL* is returned.
+ failure, ``NULL`` is returned.
.. c:function:: PyObject* PyByteArray_Concat(PyObject *a, PyObject *b)
.. c:function:: Py_ssize_t PyByteArray_Size(PyObject *bytearray)
- Return the size of *bytearray* after checking for a *NULL* pointer.
+ Return the size of *bytearray* after checking for a ``NULL`` pointer.
.. c:function:: char* PyByteArray_AsString(PyObject *bytearray)
Return the contents of *bytearray* as a char array after checking for a
- *NULL* pointer. The returned array always has an extra
+ ``NULL`` pointer. The returned array always has an extra
null byte appended.
.. c:function:: PyObject* PyBytes_FromString(const char *v)
Return a new bytes object with a copy of the string *v* as value on success,
- and *NULL* on failure. The parameter *v* must not be *NULL*; it will not be
+ and ``NULL`` on failure. The parameter *v* must not be ``NULL``; it will not be
checked.
.. c:function:: PyObject* PyBytes_FromStringAndSize(const char *v, Py_ssize_t len)
Return a new bytes object with a copy of the string *v* as value and length
- *len* on success, and *NULL* on failure. If *v* is *NULL*, the contents of
+ *len* on success, and ``NULL`` on failure. If *v* is ``NULL``, the contents of
the bytes object are uninitialized.
whether there are any other null bytes. The data must not be
modified in any way, unless the object was just created using
``PyBytes_FromStringAndSize(NULL, size)``. It must not be deallocated. If
- *o* is not a bytes object at all, :c:func:`PyBytes_AsString` returns *NULL*
+ *o* is not a bytes object at all, :c:func:`PyBytes_AsString` returns ``NULL``
and raises :exc:`TypeError`.
Return the null-terminated contents of the object *obj*
through the output variables *buffer* and *length*.
- If *length* is *NULL*, the bytes object
+ If *length* is ``NULL``, the bytes object
may not contain embedded null bytes;
if it does, the function returns ``-1`` and a :exc:`ValueError` is raised.
appended to *bytes*; the caller will own the new reference. The reference to
the old value of *bytes* will be stolen. If the new object cannot be
created, the old reference to *bytes* will still be discarded and the value
- of *\*bytes* will be set to *NULL*; the appropriate exception will be set.
+ of *\*bytes* will be set to ``NULL``; the appropriate exception will be set.
.. c:function:: void PyBytes_ConcatAndDel(PyObject **bytes, PyObject *newpart)
desired. On success, *\*bytes* holds the resized bytes object and ``0`` is
returned; the address in *\*bytes* may differ from its input value. If the
reallocation fails, the original bytes object at *\*bytes* is deallocated,
- *\*bytes* is set to *NULL*, :exc:`MemoryError` is set, and ``-1`` is
+ *\*bytes* is set to ``NULL``, :exc:`MemoryError` is set, and ``-1`` is
returned.
.. c:function:: PyObject* PyCapsule_New(void *pointer, const char *name, PyCapsule_Destructor destructor)
Create a :c:type:`PyCapsule` encapsulating the *pointer*. The *pointer*
- argument may not be *NULL*.
+ argument may not be ``NULL``.
- On failure, set an exception and return *NULL*.
+ On failure, set an exception and return ``NULL``.
- The *name* string may either be *NULL* or a pointer to a valid C string. If
- non-*NULL*, this string must outlive the capsule. (Though it is permitted to
+ The *name* string may either be ``NULL`` or a pointer to a valid C string. If
+ non-``NULL``, this string must outlive the capsule. (Though it is permitted to
free it inside the *destructor*.)
- If the *destructor* argument is not *NULL*, it will be called with the
+ If the *destructor* argument is not ``NULL``, it will be called with the
capsule as its argument when it is destroyed.
If this capsule will be stored as an attribute of a module, the *name* should
.. c:function:: void* PyCapsule_GetPointer(PyObject *capsule, const char *name)
Retrieve the *pointer* stored in the capsule. On failure, set an exception
- and return *NULL*.
+ and return ``NULL``.
The *name* parameter must compare exactly to the name stored in the capsule.
- If the name stored in the capsule is *NULL*, the *name* passed in must also
- be *NULL*. Python uses the C function :c:func:`strcmp` to compare capsule
+ If the name stored in the capsule is ``NULL``, the *name* passed in must also
+ be ``NULL``. Python uses the C function :c:func:`strcmp` to compare capsule
names.
.. c:function:: PyCapsule_Destructor PyCapsule_GetDestructor(PyObject *capsule)
Return the current destructor stored in the capsule. On failure, set an
- exception and return *NULL*.
+ exception and return ``NULL``.
- It is legal for a capsule to have a *NULL* destructor. This makes a *NULL*
+ It is legal for a capsule to have a ``NULL`` destructor. This makes a ``NULL``
return code somewhat ambiguous; use :c:func:`PyCapsule_IsValid` or
:c:func:`PyErr_Occurred` to disambiguate.
.. c:function:: void* PyCapsule_GetContext(PyObject *capsule)
Return the current context stored in the capsule. On failure, set an
- exception and return *NULL*.
+ exception and return ``NULL``.
- It is legal for a capsule to have a *NULL* context. This makes a *NULL*
+ It is legal for a capsule to have a ``NULL`` context. This makes a ``NULL``
return code somewhat ambiguous; use :c:func:`PyCapsule_IsValid` or
:c:func:`PyErr_Occurred` to disambiguate.
.. c:function:: const char* PyCapsule_GetName(PyObject *capsule)
Return the current name stored in the capsule. On failure, set an exception
- and return *NULL*.
+ and return ``NULL``.
- It is legal for a capsule to have a *NULL* name. This makes a *NULL* return
+ It is legal for a capsule to have a ``NULL`` name. This makes a ``NULL`` return
code somewhat ambiguous; use :c:func:`PyCapsule_IsValid` or
:c:func:`PyErr_Occurred` to disambiguate.
import the module conventionally (using :c:func:`PyImport_ImportModule`).
Return the capsule's internal *pointer* on success. On failure, set an
- exception and return *NULL*.
+ exception and return ``NULL``.
.. c:function:: int PyCapsule_IsValid(PyObject *capsule, const char *name)
Determines whether or not *capsule* is a valid capsule. A valid capsule is
- non-*NULL*, passes :c:func:`PyCapsule_CheckExact`, has a non-*NULL* pointer
+ non-``NULL``, passes :c:func:`PyCapsule_CheckExact`, has a non-``NULL`` pointer
stored in it, and its internal name matches the *name* parameter. (See
:c:func:`PyCapsule_GetPointer` for information on how capsule names are
compared.)
.. c:function:: int PyCapsule_SetName(PyObject *capsule, const char *name)
- Set the name inside *capsule* to *name*. If non-*NULL*, the name must
+ Set the name inside *capsule* to *name*. If non-``NULL``, the name must
outlive the capsule. If the previous *name* stored in the capsule was not
- *NULL*, no attempt is made to free it.
+ ``NULL``, no attempt is made to free it.
Return ``0`` on success. Return nonzero and set an exception on failure.
.. c:function:: int PyCapsule_SetPointer(PyObject *capsule, void *pointer)
Set the void pointer inside *capsule* to *pointer*. The pointer may not be
- *NULL*.
+ ``NULL``.
Return ``0`` on success. Return nonzero and set an exception on failure.
.. c:function:: int PyCell_Check(ob)
- Return true if *ob* is a cell object; *ob* must not be *NULL*.
+ Return true if *ob* is a cell object; *ob* must not be ``NULL``.
.. c:function:: PyObject* PyCell_New(PyObject *ob)
Create and return a new cell object containing the value *ob*. The parameter may
- be *NULL*.
+ be ``NULL``.
.. c:function:: PyObject* PyCell_Get(PyObject *cell)
.. c:function:: PyObject* PyCell_GET(PyObject *cell)
Return the contents of the cell *cell*, but without checking that *cell* is
- non-*NULL* and a cell object.
+ non-``NULL`` and a cell object.
.. c:function:: int PyCell_Set(PyObject *cell, PyObject *value)
Set the contents of the cell object *cell* to *value*. This releases the
- reference to any current content of the cell. *value* may be *NULL*. *cell*
- must be non-*NULL*; if it is not a cell object, ``-1`` will be returned. On
+ reference to any current content of the cell. *value* may be ``NULL``. *cell*
+ must be non-``NULL``; if it is not a cell object, ``-1`` will be returned. On
success, ``0`` will be returned.
.. c:function:: void PyCell_SET(PyObject *cell, PyObject *value)
Sets the value of the cell object *cell* to *value*. No reference counts are
- adjusted, and no checks are made for safety; *cell* must be non-*NULL* and must
+ adjusted, and no checks are made for safety; *cell* must be non-``NULL`` and must
be a cell object.
*object* is passed through the encoder function found for the given
*encoding* using the error handling method defined by *errors*. *errors* may
- be *NULL* to use the default method defined for the codec. Raises a
+ be ``NULL`` to use the default method defined for the codec. Raises a
:exc:`LookupError` if no encoder can be found.
.. c:function:: PyObject* PyCodec_Decode(PyObject *object, const char *encoding, const char *errors)
*object* is passed through the decoder function found for the given
*encoding* using the error handling method defined by *errors*. *errors* may
- be *NULL* to use the default method defined for the codec. Raises a
+ be ``NULL`` to use the default method defined for the codec. Raises a
:exc:`LookupError` if no encoder can be found.
In the following functions, the *encoding* string is looked up converted to all
lower-case characters, which makes encodings looked up through this mechanism
effectively case-insensitive. If no codec is found, a :exc:`KeyError` is set
-and *NULL* returned.
+and ``NULL`` returned.
.. c:function:: PyObject* PyCodec_Encoder(const char *encoding)
.. c:function:: PyObject* PyCodec_LookupError(const char *name)
Lookup the error handling callback function registered under *name*. As a
- special case *NULL* can be passed, in which case the error handling callback
+ special case ``NULL`` can be passed, in which case the error handling callback
for "strict" will be returned.
.. c:function:: PyObject* PyCodec_StrictErrors(PyObject *exc)
.. warning::
While the functions described in this chapter carefully check the type of the
- objects which are passed in, many of them do not check for *NULL* being passed
- instead of a valid object. Allowing *NULL* to be passed in can cause memory
+ objects which are passed in, many of them do not check for ``NULL`` being passed
+ instead of a valid object. Allowing ``NULL`` to be passed in can cause memory
access violations and immediate termination of the interpreter.
.. c:function:: int PyContext_CheckExact(PyObject *o)
Return true if *o* is of type :c:data:`PyContext_Type`. *o* must not be
- *NULL*. This function always succeeds.
+ ``NULL``. This function always succeeds.
.. c:function:: int PyContextVar_CheckExact(PyObject *o)
Return true if *o* is of type :c:data:`PyContextVar_Type`. *o* must not be
- *NULL*. This function always succeeds.
+ ``NULL``. This function always succeeds.
.. c:function:: int PyContextToken_CheckExact(PyObject *o)
Return true if *o* is of type :c:data:`PyContextToken_Type`.
- *o* must not be *NULL*. This function always succeeds.
+ *o* must not be ``NULL``. This function always succeeds.
Context object management functions:
*val* is a finite number, an infinite number, or not a number, respectively.
The return value is a pointer to *buffer* with the converted string or
- *NULL* if the conversion failed. The caller is responsible for freeing the
+ ``NULL`` if the conversion failed. The caller is responsible for freeing the
returned string by calling :c:func:`PyMem_Free`.
.. versionadded:: 3.1
.. c:function:: int PyCoro_CheckExact(PyObject *ob)
- Return true if *ob*'s type is *PyCoro_Type*; *ob* must not be *NULL*.
+ Return true if *ob*'s type is *PyCoro_Type*; *ob* must not be ``NULL``.
.. c:function:: PyObject* PyCoro_New(PyFrameObject *frame, PyObject *name, PyObject *qualname)
Create and return a new coroutine object based on the *frame* object,
with ``__name__`` and ``__qualname__`` set to *name* and *qualname*.
A reference to *frame* is stolen by this function. The *frame* argument
- must not be *NULL*.
+ must not be ``NULL``.
.. c:function:: int PyDate_Check(PyObject *ob)
Return true if *ob* is of type :c:data:`PyDateTime_DateType` or a subtype of
- :c:data:`PyDateTime_DateType`. *ob* must not be *NULL*.
+ :c:data:`PyDateTime_DateType`. *ob* must not be ``NULL``.
.. c:function:: int PyDate_CheckExact(PyObject *ob)
Return true if *ob* is of type :c:data:`PyDateTime_DateType`. *ob* must not be
- *NULL*.
+ ``NULL``.
.. c:function:: int PyDateTime_Check(PyObject *ob)
Return true if *ob* is of type :c:data:`PyDateTime_DateTimeType` or a subtype of
- :c:data:`PyDateTime_DateTimeType`. *ob* must not be *NULL*.
+ :c:data:`PyDateTime_DateTimeType`. *ob* must not be ``NULL``.
.. c:function:: int PyDateTime_CheckExact(PyObject *ob)
Return true if *ob* is of type :c:data:`PyDateTime_DateTimeType`. *ob* must not
- be *NULL*.
+ be ``NULL``.
.. c:function:: int PyTime_Check(PyObject *ob)
Return true if *ob* is of type :c:data:`PyDateTime_TimeType` or a subtype of
- :c:data:`PyDateTime_TimeType`. *ob* must not be *NULL*.
+ :c:data:`PyDateTime_TimeType`. *ob* must not be ``NULL``.
.. c:function:: int PyTime_CheckExact(PyObject *ob)
Return true if *ob* is of type :c:data:`PyDateTime_TimeType`. *ob* must not be
- *NULL*.
+ ``NULL``.
.. c:function:: int PyDelta_Check(PyObject *ob)
Return true if *ob* is of type :c:data:`PyDateTime_DeltaType` or a subtype of
- :c:data:`PyDateTime_DeltaType`. *ob* must not be *NULL*.
+ :c:data:`PyDateTime_DeltaType`. *ob* must not be ``NULL``.
.. c:function:: int PyDelta_CheckExact(PyObject *ob)
Return true if *ob* is of type :c:data:`PyDateTime_DeltaType`. *ob* must not be
- *NULL*.
+ ``NULL``.
.. c:function:: int PyTZInfo_Check(PyObject *ob)
Return true if *ob* is of type :c:data:`PyDateTime_TZInfoType` or a subtype of
- :c:data:`PyDateTime_TZInfoType`. *ob* must not be *NULL*.
+ :c:data:`PyDateTime_TZInfoType`. *ob* must not be ``NULL``.
.. c:function:: int PyTZInfo_CheckExact(PyObject *ob)
Return true if *ob* is of type :c:data:`PyDateTime_TZInfoType`. *ob* must not be
- *NULL*.
+ ``NULL``.
Macros to create objects:
Macros to extract fields from date objects. The argument must be an instance of
:c:data:`PyDateTime_Date`, including subclasses (such as
-:c:data:`PyDateTime_DateTime`). The argument must not be *NULL*, and the type is
+:c:data:`PyDateTime_DateTime`). The argument must not be ``NULL``, and the type is
not checked:
.. c:function:: int PyDateTime_GET_YEAR(PyDateTime_Date *o)
Macros to extract fields from datetime objects. The argument must be an
instance of :c:data:`PyDateTime_DateTime`, including subclasses. The argument
-must not be *NULL*, and the type is not checked:
+must not be ``NULL``, and the type is not checked:
.. c:function:: int PyDateTime_DATE_GET_HOUR(PyDateTime_DateTime *o)
Macros to extract fields from time objects. The argument must be an instance of
-:c:data:`PyDateTime_Time`, including subclasses. The argument must not be *NULL*,
+:c:data:`PyDateTime_Time`, including subclasses. The argument must not be ``NULL``,
and the type is not checked:
.. c:function:: int PyDateTime_TIME_GET_HOUR(PyDateTime_Time *o)
Macros to extract fields from time delta objects. The argument must be an
instance of :c:data:`PyDateTime_Delta`, including subclasses. The argument must
-not be *NULL*, and the type is not checked:
+not be ``NULL``, and the type is not checked:
.. c:function:: int PyDateTime_DELTA_GET_DAYS(PyDateTime_Delta *o)
.. c:function:: PyObject* PyDict_New()
- Return a new empty dictionary, or *NULL* on failure.
+ Return a new empty dictionary, or ``NULL`` on failure.
.. c:function:: PyObject* PyDictProxy_New(PyObject *mapping)
.. c:function:: PyObject* PyDict_GetItem(PyObject *p, PyObject *key)
- Return the object from dictionary *p* which has a key *key*. Return *NULL*
+ Return the object from dictionary *p* which has a key *key*. Return ``NULL``
if the key *key* is not present, but *without* setting an exception.
Note that exceptions which occur while calling :meth:`__hash__` and
.. c:function:: PyObject* PyDict_GetItemWithError(PyObject *p, PyObject *key)
Variant of :c:func:`PyDict_GetItem` that does not suppress
- exceptions. Return *NULL* **with** an exception set if an exception
- occurred. Return *NULL* **without** an exception set if the key
+ exceptions. Return ``NULL`` **with** an exception set if an exception
+ occurred. Return ``NULL`` **without** an exception set if the key
wasn't present.
function returns true for each pair in the dictionary, and false once all
pairs have been reported. The parameters *pkey* and *pvalue* should either
point to :c:type:`PyObject\*` variables that will be filled in with each key
- and value, respectively, or may be *NULL*. Any references returned through
+ and value, respectively, or may be ``NULL``. Any references returned through
them are borrowed. *ppos* should not be altered during iteration. Its
value represents offsets within the internal dictionary structure, and
since the structure is sparse, the offsets are not consecutive.
there is a global indicator (per thread) of the last error that occurred. Most
C API functions don't clear this on success, but will set it to indicate the
cause of the error on failure. Most C API functions also return an error
-indicator, usually *NULL* if they are supposed to return a pointer, or ``-1``
+indicator, usually ``NULL`` if they are supposed to return a pointer, or ``-1``
if they return an integer (exception: the :c:func:`PyArg_\*` functions
return ``1`` for success and ``0`` for failure).
.. c:function:: PyObject* PyErr_Format(PyObject *exception, const char *format, ...)
- This function sets the error indicator and returns *NULL*. *exception*
+ This function sets the error indicator and returns ``NULL``. *exception*
should be a Python exception class. The *format* and subsequent
parameters help format the error message; they have the same meaning and
values as in :c:func:`PyUnicode_FromFormat`. *format* is an ASCII-encoded
.. c:function:: PyObject* PyErr_NoMemory()
- This is a shorthand for ``PyErr_SetNone(PyExc_MemoryError)``; it returns *NULL*
+ This is a shorthand for ``PyErr_SetNone(PyExc_MemoryError)``; it returns ``NULL``
so an object allocation function can write ``return PyErr_NoMemory();`` when it
runs out of memory.
and then calls ``PyErr_SetObject(type, object)``. On Unix, when the
:c:data:`errno` value is :const:`EINTR`, indicating an interrupted system call,
this calls :c:func:`PyErr_CheckSignals`, and if that set the error indicator,
- leaves it set to that. The function always returns *NULL*, so a wrapper
+ leaves it set to that. The function always returns ``NULL``, so a wrapper
function around a system call can write ``return PyErr_SetFromErrno(type);``
when the system call returns an error.
.. c:function:: PyObject* PyErr_SetFromErrnoWithFilenameObject(PyObject *type, PyObject *filenameObject)
Similar to :c:func:`PyErr_SetFromErrno`, with the additional behavior that if
- *filenameObject* is not *NULL*, it is passed to the constructor of *type* as
+ *filenameObject* is not ``NULL``, it is passed to the constructor of *type* as
a third parameter. In the case of :exc:`OSError` exception,
this is used to define the :attr:`filename` attribute of the
exception instance.
then it constructs a tuple object whose first item is the *ierr* value and whose
second item is the corresponding error message (gotten from
:c:func:`FormatMessage`), and then calls ``PyErr_SetObject(PyExc_WindowsError,
- object)``. This function always returns *NULL*.
+ object)``. This function always returns ``NULL``.
.. availability:: Windows.
.. c:function:: int PyErr_WarnEx(PyObject *category, const char *message, Py_ssize_t stack_level)
Issue a warning message. The *category* argument is a warning category (see
- below) or *NULL*; the *message* argument is a UTF-8 encoded string. *stack_level* is a
+ below) or ``NULL``; the *message* argument is a UTF-8 encoded string. *stack_level* is a
positive number giving a number of stack frames; the warning will be issued from
the currently executing line of code in that stack frame. A *stack_level* of 1
is the function calling :c:func:`PyErr_WarnEx`, 2 is the function above that,
Issue a warning message with explicit control over all warning attributes. This
is a straightforward wrapper around the Python function
:func:`warnings.warn_explicit`, see there for more information. The *module*
- and *registry* arguments may be set to *NULL* to get the default effect
+ and *registry* arguments may be set to ``NULL`` to get the default effect
described there.
.. versionadded:: 3.4
Test whether the error indicator is set. If set, return the exception *type*
(the first argument to the last call to one of the :c:func:`PyErr_Set\*`
- functions or to :c:func:`PyErr_Restore`). If not set, return *NULL*. You do not
+ functions or to :c:func:`PyErr_Restore`). If not set, return ``NULL``. You do not
own a reference to the return value, so you do not need to :c:func:`Py_DECREF`
it.
.. c:function:: void PyErr_Fetch(PyObject **ptype, PyObject **pvalue, PyObject **ptraceback)
Retrieve the error indicator into three variables whose addresses are passed.
- If the error indicator is not set, set all three variables to *NULL*. If it is
+ If the error indicator is not set, set all three variables to ``NULL``. If it is
set, it will be cleared and you own a reference to each object retrieved. The
- value and traceback object may be *NULL* even when the type object is not.
+ value and traceback object may be ``NULL`` even when the type object is not.
.. note::
.. c:function:: void PyErr_Restore(PyObject *type, PyObject *value, PyObject *traceback)
Set the error indicator from the three objects. If the error indicator is
- already set, it is cleared first. If the objects are *NULL*, the error
- indicator is cleared. Do not pass a *NULL* type and non-*NULL* value or
+ already set, it is cleared first. If the objects are ``NULL``, the error
+ indicator is cleared. Do not pass a ``NULL`` type and non-``NULL`` value or
traceback. The exception type should be a class. Do not pass an invalid
exception type or value. (Violating these rules will cause subtle problems
later.) This call takes away a reference to each object: you must own a
Retrieve the exception info, as known from ``sys.exc_info()``. This refers
to an exception that was *already caught*, not to an exception that was
freshly raised. Returns new references for the three objects, any of which
- may be *NULL*. Does not modify the exception info state.
+ may be ``NULL``. Does not modify the exception info state.
.. note::
Set the exception info, as known from ``sys.exc_info()``. This refers
to an exception that was *already caught*, not to an exception that was
freshly raised. This function steals the references of the arguments.
- To clear the exception state, pass *NULL* for all three arguments.
+ To clear the exception state, pass ``NULL`` for all three arguments.
For general rules about the three arguments, see :c:func:`PyErr_Restore`.
.. note::
This utility function creates and returns a new exception class. The *name*
argument must be the name of the new exception, a C string of the form
- ``module.classname``. The *base* and *dict* arguments are normally *NULL*.
+ ``module.classname``. The *base* and *dict* arguments are normally ``NULL``.
This creates a class object derived from :exc:`Exception` (accessible in C as
:c:data:`PyExc_Exception`).
.. c:function:: PyObject* PyErr_NewExceptionWithDoc(const char *name, const char *doc, PyObject *base, PyObject *dict)
Same as :c:func:`PyErr_NewException`, except that the new exception class can
- easily be given a docstring: If *doc* is non-*NULL*, it will be used as the
+ easily be given a docstring: If *doc* is non-``NULL``, it will be used as the
docstring for the exception class.
.. versionadded:: 3.2
Return the traceback associated with the exception as a new reference, as
accessible from Python through :attr:`__traceback__`. If there is no
- traceback associated, this returns *NULL*.
+ traceback associated, this returns ``NULL``.
.. c:function:: int PyException_SetTraceback(PyObject *ex, PyObject *tb)
Return the context (another exception instance during whose handling *ex* was
raised) associated with the exception as a new reference, as accessible from
Python through :attr:`__context__`. If there is no context associated, this
- returns *NULL*.
+ returns ``NULL``.
.. c:function:: void PyException_SetContext(PyObject *ex, PyObject *ctx)
- Set the context associated with the exception to *ctx*. Use *NULL* to clear
+ Set the context associated with the exception to *ctx*. Use ``NULL`` to clear
it. There is no type check to make sure that *ctx* is an exception instance.
This steals a reference to *ctx*.
.. c:function:: void PyException_SetCause(PyObject *ex, PyObject *cause)
- Set the cause associated with the exception to *cause*. Use *NULL* to clear
+ Set the cause associated with the exception to *cause*. Use ``NULL`` to clear
it. There is no type check to make sure that *cause* is either an exception
instance or :const:`None`. This steals a reference to *cause*.
int PyUnicodeTranslateError_GetStart(PyObject *exc, Py_ssize_t *start)
Get the *start* attribute of the given exception object and place it into
- *\*start*. *start* must not be *NULL*. Return ``0`` on success, ``-1`` on
+ *\*start*. *start* must not be ``NULL``. Return ``0`` on success, ``-1`` on
failure.
.. c:function:: int PyUnicodeDecodeError_SetStart(PyObject *exc, Py_ssize_t start)
int PyUnicodeTranslateError_GetEnd(PyObject *exc, Py_ssize_t *end)
Get the *end* attribute of the given exception object and place it into
- *\*end*. *end* must not be *NULL*. Return ``0`` on success, ``-1`` on
+ *\*end*. *end* must not be ``NULL``. Return ``0`` on success, ``-1`` on
failure.
.. c:function:: int PyUnicodeDecodeError_SetEnd(PyObject *exc, Py_ssize_t end)
Create a Python file object from the file descriptor of an already
opened file *fd*. The arguments *name*, *encoding*, *errors* and *newline*
- can be *NULL* to use the defaults; *buffering* can be *-1* to use the
+ can be ``NULL`` to use the defaults; *buffering* can be *-1* to use the
default. *name* is ignored and kept for backward compatibility. Return
- *NULL* on failure. For a more comprehensive description of the arguments,
+ ``NULL`` on failure. For a more comprehensive description of the arguments,
please refer to the :func:`io.open` function documentation.
.. warning::
.. c:function:: PyObject* PyFloat_FromString(PyObject *str)
Create a :c:type:`PyFloatObject` object based on the string value in *str*, or
- *NULL* on failure.
+ ``NULL`` on failure.
.. c:function:: PyObject* PyFloat_FromDouble(double v)
- Create a :c:type:`PyFloatObject` object from *v*, or *NULL* on failure.
+ Create a :c:type:`PyFloatObject` object from *v*, or ``NULL`` on failure.
.. c:function:: double PyFloat_AsDouble(PyObject *pyfloat)
.. c:function:: int PyFunction_Check(PyObject *o)
Return true if *o* is a function object (has type :c:data:`PyFunction_Type`).
- The parameter must not be *NULL*.
+ The parameter must not be ``NULL``.
.. c:function:: PyObject* PyFunction_New(PyObject *code, PyObject *globals)
The function's docstring and name are retrieved from the code object. *__module__*
is retrieved from *globals*. The argument defaults, annotations and closure are
- set to *NULL*. *__qualname__* is set to the same value as the function's name.
+ set to ``NULL``. *__qualname__* is set to the same value as the function's name.
.. c:function:: PyObject* PyFunction_NewWithQualName(PyObject *code, PyObject *globals, PyObject *qualname)
.. c:function:: PyObject* PyFunction_GetDefaults(PyObject *op)
Return the argument default values of the function object *op*. This can be a
- tuple of arguments or *NULL*.
+ tuple of arguments or ``NULL``.
.. c:function:: int PyFunction_SetDefaults(PyObject *op, PyObject *defaults)
.. c:function:: PyObject* PyFunction_GetClosure(PyObject *op)
- Return the closure associated with the function object *op*. This can be *NULL*
+ Return the closure associated with the function object *op*. This can be ``NULL``
or a tuple of cell objects.
.. c:function:: PyObject *PyFunction_GetAnnotations(PyObject *op)
Return the annotations of the function object *op*. This can be a
- mutable dictionary or *NULL*.
+ mutable dictionary or ``NULL``.
.. c:function:: int PyFunction_SetAnnotations(PyObject *op, PyObject *annotations)
.. c:function:: TYPE* PyObject_GC_Resize(TYPE, PyVarObject *op, Py_ssize_t newsize)
Resize an object allocated by :c:func:`PyObject_NewVar`. Returns the
- resized object or *NULL* on failure. *op* must not be tracked by the collector yet.
+ resized object or ``NULL`` on failure. *op* must not be tracked by the collector yet.
.. c:function:: void PyObject_GC_Track(PyObject *op)
Traversal function for a container object. Implementations must call the
*visit* function for each object directly contained by *self*, with the
parameters to *visit* being the contained object and the *arg* value passed
- to the handler. The *visit* function must not be called with a *NULL*
+ to the handler. The *visit* function must not be called with a ``NULL``
object argument. If *visit* returns a non-zero value that value should be
returned immediately.
.. c:function:: void Py_VISIT(PyObject *o)
- If *o* is not *NULL*, call the *visit* callback, with arguments *o*
+ If *o* is not ``NULL``, call the *visit* callback, with arguments *o*
and *arg*. If *visit* returns a non-zero value, then return it.
Using this macro, :c:member:`~PyTypeObject.tp_traverse` handlers
look like::
return 0;
}
-The :c:member:`~PyTypeObject.tp_clear` handler must be of the :c:type:`inquiry` type, or *NULL*
+The :c:member:`~PyTypeObject.tp_clear` handler must be of the :c:type:`inquiry` type, or ``NULL``
if the object is immutable.
.. c:function:: int PyGen_Check(PyObject *ob)
- Return true if *ob* is a generator object; *ob* must not be *NULL*.
+ Return true if *ob* is a generator object; *ob* must not be ``NULL``.
.. c:function:: int PyGen_CheckExact(PyObject *ob)
- Return true if *ob*'s type is *PyGen_Type*; *ob* must not be *NULL*.
+ Return true if *ob*'s type is *PyGen_Type*; *ob* must not be ``NULL``.
.. c:function:: PyObject* PyGen_New(PyFrameObject *frame)
Create and return a new generator object based on the *frame* object.
A reference to *frame* is stolen by this function. The argument must not be
- *NULL*.
+ ``NULL``.
.. c:function:: PyObject* PyGen_NewWithQualName(PyFrameObject *frame, PyObject *name, PyObject *qualname)
Create and return a new generator object based on the *frame* object,
with ``__name__`` and ``__qualname__`` set to *name* and *qualname*.
A reference to *frame* is stolen by this function. The *frame* argument
- must not be *NULL*.
+ must not be ``NULL``.
single: modules (in module sys)
This is a simplified interface to :c:func:`PyImport_ImportModuleEx` below,
- leaving the *globals* and *locals* arguments set to *NULL* and *level* set
+ leaving the *globals* and *locals* arguments set to ``NULL`` and *level* set
to 0. When the *name*
argument contains a dot (when it specifies a submodule of a package), the
*fromlist* argument is set to the list ``['*']`` so that the return value is the
be the case. (Unfortunately, this has an additional side effect when *name* in
fact specifies a subpackage instead of a submodule: the submodules specified in
the package's ``__all__`` variable are loaded.) Return a new reference to the
- imported module, or *NULL* with an exception set on failure. A failing
+ imported module, or ``NULL`` with an exception set on failure. A failing
import of a module doesn't leave the module in :data:`sys.modules`.
This function always uses absolute imports.
function :func:`__import__`.
The return value is a new reference to the imported module or top-level
- package, or *NULL* with an exception set on failure. Like for
+ package, or ``NULL`` with an exception set on failure. Like for
:func:`__import__`, the return value when a submodule of a package was
requested is normally the top-level package, unless a non-empty *fromlist*
was given.
this function directly.
The return value is a new reference to the imported module or top-level package,
- or *NULL* with an exception set on failure. Like for :func:`__import__`,
+ or ``NULL`` with an exception set on failure. Like for :func:`__import__`,
the return value when a submodule of a package was requested is normally the
top-level package, unless a non-empty *fromlist* was given.
.. c:function:: PyObject* PyImport_ReloadModule(PyObject *m)
- Reload a module. Return a new reference to the reloaded module, or *NULL* with
+ Reload a module. Return a new reference to the reloaded module, or ``NULL`` with
an exception set on failure (the module still exists in this case).
Return the module object corresponding to a module name. The *name* argument
may be of the form ``package.module``. First check the modules dictionary if
there's one there, and if not, create a new one and insert it in the modules
- dictionary. Return *NULL* with an exception set on failure.
+ dictionary. Return ``NULL`` with an exception set on failure.
.. note::
Given a module name (possibly of the form ``package.module``) and a code object
read from a Python bytecode file or obtained from the built-in function
:func:`compile`, load the module. Return a new reference to the module object,
- or *NULL* with an exception set if an error occurred. *name*
+ or ``NULL`` with an exception set if an error occurred. *name*
is removed from :attr:`sys.modules` in error cases, even if *name* was already
in :attr:`sys.modules` on entry to :c:func:`PyImport_ExecCodeModule`. Leaving
incompletely initialized modules in :attr:`sys.modules` is dangerous, as imports of
.. c:var:: const struct _frozen* PyImport_FrozenModules
This pointer is initialized to point to an array of :c:type:`struct _frozen`
- records, terminated by one whose members are all *NULL* or zero. When a frozen
+ records, terminated by one whose members are all ``NULL`` or zero. When a frozen
module is imported, it is searched in this table. Third-party code could play
tricks with this to provide a dynamically created collection of frozen modules.
.. c:function:: int PyImport_ExtendInittab(struct _inittab *newtab)
Add a collection of modules to the table of built-in modules. The *newtab*
- array must end with a sentinel entry which contains *NULL* for the :attr:`name`
+ array must end with a sentinel entry which contains ``NULL`` for the :attr:`name`
field; failure to provide the sentinel value can result in a memory fault.
Returns ``0`` on success or ``-1`` if insufficient memory could be allocated to
extend the internal table. In the event of failure, no modules are added to the
.. c:function:: PyThreadState* PyEval_SaveThread()
Release the global interpreter lock (if it has been created and thread
- support is enabled) and reset the thread state to *NULL*, returning the
- previous thread state (which is not *NULL*). If the lock has been created,
+ support is enabled) and reset the thread state to ``NULL``, returning the
+ previous thread state (which is not ``NULL``). If the lock has been created,
the current thread must have acquired it.
Acquire the global interpreter lock (if it has been created and thread
support is enabled) and set the thread state to *tstate*, which must not be
- *NULL*. If the lock has been created, the current thread must not have
+ ``NULL``. If the lock has been created, the current thread must not have
acquired it, otherwise deadlock ensues.
.. note::
.. c:function:: PyThreadState* PyThreadState_Get()
Return the current thread state. The global interpreter lock must be held.
- When the current thread state is *NULL*, this issues a fatal error (so that
- the caller needn't check for *NULL*).
+ When the current thread state is ``NULL``, this issues a fatal error (so that
+ the caller needn't check for ``NULL``).
.. c:function:: PyThreadState* PyThreadState_Swap(PyThreadState *tstate)
Swap the current thread state with the thread state given by the argument
- *tstate*, which may be *NULL*. The global interpreter lock must be held
+ *tstate*, which may be ``NULL``. The global interpreter lock must be held
and is not released.
Return a dictionary in which extensions can store thread-specific state
information. Each extension should use a unique key to use to store state in
the dictionary. It is okay to call this function when no current thread state
- is available. If this function returns *NULL*, no exception has been raised and
+ is available. If this function returns ``NULL``, no exception has been raised and
the caller should assume no current thread state is available.
.. c:function:: void PyEval_AcquireThread(PyThreadState *tstate)
Acquire the global interpreter lock and set the current thread state to
- *tstate*, which should not be *NULL*. The lock must have been created earlier.
+ *tstate*, which should not be ``NULL``. The lock must have been created earlier.
If this thread already has the lock, deadlock ensues.
:c:func:`PyEval_RestoreThread` is a higher-level function which is always
.. c:function:: void PyEval_ReleaseThread(PyThreadState *tstate)
- Reset the current thread state to *NULL* and release the global interpreter
+ Reset the current thread state to ``NULL`` and release the global interpreter
lock. The lock must have been created earlier and must be held by the current
- thread. The *tstate* argument, which must not be *NULL*, is only used to check
+ thread. The *tstate* argument, which must not be ``NULL``, is only used to check
that it represents the current thread state --- if it isn't, a fatal error is
reported.
The return value points to the first thread state created in the new
sub-interpreter. This thread state is made in the current thread state.
Note that no actual thread is created; see the discussion of thread states
- below. If creation of the new interpreter is unsuccessful, *NULL* is
+ below. If creation of the new interpreter is unsuccessful, ``NULL`` is
returned; no exception is set since the exception state is stored in the
current thread state and there may not be a current thread state. (Like all
other Python/C API functions, the global interpreter lock must be held before
Destroy the (sub-)interpreter represented by the given thread state. The given
thread state must be the current thread state. See the discussion of thread
- states below. When the call returns, the current thread state is *NULL*. All
+ states below. When the call returns, the current thread state is ``NULL``. All
thread states associated with this interpreter are destroyed. (The global
interpreter lock must be held before calling this function and is still held
when it returns.) :c:func:`Py_FinalizeEx` will destroy all sub-interpreters that
:const:`PyTrace_C_CALL`, :const:`PyTrace_C_EXCEPTION`, :const:`PyTrace_C_RETURN`,
or :const:`PyTrace_OPCODE`, and *arg* depends on the value of *what*:
- +------------------------------+--------------------------------------+
- | Value of *what* | Meaning of *arg* |
- +==============================+======================================+
- | :const:`PyTrace_CALL` | Always :c:data:`Py_None`. |
- +------------------------------+--------------------------------------+
- | :const:`PyTrace_EXCEPTION` | Exception information as returned by |
- | | :func:`sys.exc_info`. |
- +------------------------------+--------------------------------------+
- | :const:`PyTrace_LINE` | Always :c:data:`Py_None`. |
- +------------------------------+--------------------------------------+
- | :const:`PyTrace_RETURN` | Value being returned to the caller, |
- | | or *NULL* if caused by an exception. |
- +------------------------------+--------------------------------------+
- | :const:`PyTrace_C_CALL` | Function object being called. |
- +------------------------------+--------------------------------------+
- | :const:`PyTrace_C_EXCEPTION` | Function object being called. |
- +------------------------------+--------------------------------------+
- | :const:`PyTrace_C_RETURN` | Function object being called. |
- +------------------------------+--------------------------------------+
- | :const:`PyTrace_OPCODE` | Always :c:data:`Py_None`. |
- +------------------------------+--------------------------------------+
+ +------------------------------+----------------------------------------+
+ | Value of *what* | Meaning of *arg* |
+ +==============================+========================================+
+ | :const:`PyTrace_CALL` | Always :c:data:`Py_None`. |
+ +------------------------------+----------------------------------------+
+ | :const:`PyTrace_EXCEPTION` | Exception information as returned by |
+ | | :func:`sys.exc_info`. |
+ +------------------------------+----------------------------------------+
+ | :const:`PyTrace_LINE` | Always :c:data:`Py_None`. |
+ +------------------------------+----------------------------------------+
+ | :const:`PyTrace_RETURN` | Value being returned to the caller, |
+ | | or ``NULL`` if caused by an exception. |
+ +------------------------------+----------------------------------------+
+ | :const:`PyTrace_C_CALL` | Function object being called. |
+ +------------------------------+----------------------------------------+
+ | :const:`PyTrace_C_EXCEPTION` | Function object being called. |
+ +------------------------------+----------------------------------------+
+ | :const:`PyTrace_C_RETURN` | Function object being called. |
+ +------------------------------+----------------------------------------+
+ | :const:`PyTrace_OPCODE` | Always :c:data:`Py_None`. |
+ +------------------------------+----------------------------------------+
.. c:var:: int PyTrace_CALL
.. c:function:: void PyEval_SetProfile(Py_tracefunc func, PyObject *obj)
Set the profiler function to *func*. The *obj* parameter is passed to the
- function as its first parameter, and may be any Python object, or *NULL*. If
+ function as its first parameter, and may be any Python object, or ``NULL``. If
the profile function needs to maintain state, using a different value for *obj*
for each thread provides a convenient and thread-safe place to store it. The
profile function is called for all monitored events except :const:`PyTrace_LINE`
.. c:function:: Py_tss_t* PyThread_tss_alloc()
Return a value which is the same state as a value initialized with
- :c:macro:`Py_tss_NEEDS_INIT`, or *NULL* in the case of dynamic allocation
+ :c:macro:`Py_tss_NEEDS_INIT`, or ``NULL`` in the case of dynamic allocation
failure.
Methods
~~~~~~~
-The parameter *key* of these functions must not be *NULL*. Moreover, the
+The parameter *key* of these functions must not be ``NULL``. Moreover, the
behaviors of :c:func:`PyThread_tss_set` and :c:func:`PyThread_tss_get` are
undefined if the given :c:type:`Py_tss_t` has not been initialized by
:c:func:`PyThread_tss_create`.
.. c:function:: void* PyThread_tss_get(Py_tss_t *key)
Return the :c:type:`void\*` value associated with a TSS key in the current
- thread. This returns *NULL* if no value is associated with the key in the
+ thread. This returns ``NULL`` if no value is associated with the key in the
current thread.
.. c:macro:: Py_GETENV(s)
- Like ``getenv(s)``, but returns *NULL* if :option:`-E` was passed on the
+ Like ``getenv(s)``, but returns ``NULL`` if :option:`-E` was passed on the
command line (i.e. if ``Py_IgnoreEnvironmentFlag`` is set).
.. c:macro:: Py_UNUSED(arg)
made otherwise in a function's documentation. In general, when a function
encounters an error, it sets an exception, discards any object references that
it owns, and returns an error indicator. If not documented otherwise, this
-indicator is either *NULL* or ``-1``, depending on the function's return type.
+indicator is either ``NULL`` or ``-1``, depending on the function's return type.
A few functions return a Boolean true/false result, with false indicating an
error. Very few functions return no explicit error indicator or have an
ambiguous return value, and require explicit testing for errors with
two states: an exception has occurred, or not. The function
:c:func:`PyErr_Occurred` can be used to check for this: it returns a borrowed
reference to the exception type object when an exception has occurred, and
-*NULL* otherwise. There are a number of functions to set the exception state:
+``NULL`` otherwise. There are a number of functions to set the exception state:
:c:func:`PyErr_SetString` is the most common (though not the most general)
function to set the exception state, and :c:func:`PyErr_Clear` clears the
exception state.
The full exception state consists of three objects (all of which can be
-*NULL*): the exception type, the corresponding exception value, and the
+``NULL``): the exception type, the corresponding exception value, and the
traceback. These have the same meanings as the Python result of
``sys.exc_info()``; however, they are not the same: the Python objects represent
the last exception being handled by a Python :keyword:`try` ...
This example represents an endorsed use of the ``goto`` statement in C!
It illustrates the use of :c:func:`PyErr_ExceptionMatches` and
:c:func:`PyErr_Clear` to handle specific exceptions, and the use of
-:c:func:`Py_XDECREF` to dispose of owned references that may be *NULL* (note the
+:c:func:`Py_XDECREF` to dispose of owned references that may be ``NULL`` (note the
``'X'`` in the name; :c:func:`Py_DECREF` would crash when confronted with a
-*NULL* reference). It is important that the variables used to hold owned
-references are initialized to *NULL* for this to work; likewise, the proposed
+``NULL`` reference). It is important that the variables used to hold owned
+references are initialized to ``NULL`` for this to work; likewise, the proposed
return value is initialized to ``-1`` (failure) and only set to success after
the final call made is successful.
Return the next value from the iteration *o*. The object must be an iterator
(it is up to the caller to check this). If there are no remaining values,
- returns *NULL* with no exception set. If an error occurs while retrieving
- the item, returns *NULL* and passes along the exception.
+ returns ``NULL`` with no exception set. If an error occurs while retrieving
+ the item, returns ``NULL`` and passes along the exception.
To write a loop which iterates over an iterator, the C code should look
something like this::
.. c:function:: PyObject* PyList_New(Py_ssize_t len)
- Return a new list of length *len* on success, or *NULL* on failure.
+ Return a new list of length *len* on success, or ``NULL`` on failure.
.. note::
Return the object at position *index* in the list pointed to by *list*. The
position must be non-negative; indexing from the end of the list is not
supported. If *index* is out of bounds (<0 or >=len(list)),
- return *NULL* and set an :exc:`IndexError` exception.
+ return ``NULL`` and set an :exc:`IndexError` exception.
.. c:function:: PyObject* PyList_GET_ITEM(PyObject *list, Py_ssize_t i)
.. c:function:: PyObject* PyList_GetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high)
Return a list of the objects in *list* containing the objects *between* *low*
- and *high*. Return *NULL* and set an exception if unsuccessful. Analogous
+ and *high*. Return ``NULL`` and set an exception if unsuccessful. Analogous
to ``list[low:high]``. Indexing from the end of the list is not supported.
Set the slice of *list* between *low* and *high* to the contents of
*itemlist*. Analogous to ``list[low:high] = itemlist``. The *itemlist* may
- be *NULL*, indicating the assignment of an empty list (slice deletion).
+ be ``NULL``, indicating the assignment of an empty list (slice deletion).
Return ``0`` on success, ``-1`` on failure. Indexing from the end of the
list is not supported.
.. c:function:: PyObject* PyLong_FromLong(long v)
- Return a new :c:type:`PyLongObject` object from *v*, or *NULL* on failure.
+ Return a new :c:type:`PyLongObject` object from *v*, or ``NULL`` on failure.
The current implementation keeps an array of integer objects for all integers
between ``-5`` and ``256``, when you create an int in that range you actually
.. c:function:: PyObject* PyLong_FromUnsignedLong(unsigned long v)
Return a new :c:type:`PyLongObject` object from a C :c:type:`unsigned long`, or
- *NULL* on failure.
+ ``NULL`` on failure.
.. c:function:: PyObject* PyLong_FromSsize_t(Py_ssize_t v)
Return a new :c:type:`PyLongObject` object from a C :c:type:`Py_ssize_t`, or
- *NULL* on failure.
+ ``NULL`` on failure.
.. c:function:: PyObject* PyLong_FromSize_t(size_t v)
Return a new :c:type:`PyLongObject` object from a C :c:type:`size_t`, or
- *NULL* on failure.
+ ``NULL`` on failure.
.. c:function:: PyObject* PyLong_FromLongLong(long long v)
- Return a new :c:type:`PyLongObject` object from a C :c:type:`long long`, or *NULL*
+ Return a new :c:type:`PyLongObject` object from a C :c:type:`long long`, or ``NULL``
on failure.
.. c:function:: PyObject* PyLong_FromUnsignedLongLong(unsigned long long v)
Return a new :c:type:`PyLongObject` object from a C :c:type:`unsigned long long`,
- or *NULL* on failure.
+ or ``NULL`` on failure.
.. c:function:: PyObject* PyLong_FromDouble(double v)
Return a new :c:type:`PyLongObject` object from the integer part of *v*, or
- *NULL* on failure.
+ ``NULL`` on failure.
.. c:function:: PyObject* PyLong_FromString(const char *str, char **pend, int base)
Return a new :c:type:`PyLongObject` based on the string value in *str*, which
- is interpreted according to the radix in *base*. If *pend* is non-*NULL*,
+ is interpreted according to the radix in *base*. If *pend* is non-``NULL``,
*\*pend* will point to the first character in *str* which follows the
representation of the number. If *base* is ``0``, *str* is interpreted using
the :ref:`integers` definition; in this case, leading zeros in a
is only assured to produce a usable :c:type:`void` pointer for values created
with :c:func:`PyLong_FromVoidPtr`.
- Returns *NULL* on error. Use :c:func:`PyErr_Occurred` to disambiguate.
+ Returns ``NULL`` on error. Use :c:func:`PyErr_Occurred` to disambiguate.
.. c:function:: PyObject* PyMapping_GetItemString(PyObject *o, const char *key)
- Return element of *o* corresponding to the string *key* or *NULL* on failure.
+ Return element of *o* corresponding to the string *key* or ``NULL`` on failure.
This is the equivalent of the Python expression ``o[key]``.
See also :c:func:`PyObject_GetItem`.
.. c:function:: PyObject* PyMapping_Keys(PyObject *o)
On success, return a list of the keys in object *o*. On failure, return
- *NULL*.
+ ``NULL``.
.. versionchanged:: 3.7
Previously, the function returned a list or a tuple.
.. c:function:: PyObject* PyMapping_Values(PyObject *o)
On success, return a list of the values in object *o*. On failure, return
- *NULL*.
+ ``NULL``.
.. versionchanged:: 3.7
Previously, the function returned a list or a tuple.
.. c:function:: PyObject* PyMapping_Items(PyObject *o)
On success, return a list of the items in object *o*, where each item is a
- tuple containing a key-value pair. On failure, return *NULL*.
+ tuple containing a key-value pair. On failure, return ``NULL``.
.. versionchanged:: 3.7
Previously, the function returned a list or a tuple.
reading.
On error, sets the appropriate exception (:exc:`EOFError`, :exc:`ValueError`
- or :exc:`TypeError`) and returns *NULL*.
+ or :exc:`TypeError`) and returns ``NULL``.
.. c:function:: PyObject* PyMarshal_ReadLastObjectFromFile(FILE *file)
anything else from the file.
On error, sets the appropriate exception (:exc:`EOFError`, :exc:`ValueError`
- or :exc:`TypeError`) and returns *NULL*.
+ or :exc:`TypeError`) and returns ``NULL``.
.. c:function:: PyObject* PyMarshal_ReadObjectFromString(const char *data, Py_ssize_t len)
containing *len* bytes pointed to by *data*.
On error, sets the appropriate exception (:exc:`EOFError`, :exc:`ValueError`
- or :exc:`TypeError`) and returns *NULL*.
+ or :exc:`TypeError`) and returns ``NULL``.
.. c:function:: void* PyMem_RawMalloc(size_t n)
Allocates *n* bytes and returns a pointer of type :c:type:`void\*` to the
- allocated memory, or *NULL* if the request fails.
+ allocated memory, or ``NULL`` if the request fails.
- Requesting zero bytes returns a distinct non-*NULL* pointer if possible, as
+ Requesting zero bytes returns a distinct non-``NULL`` pointer if possible, as
if ``PyMem_RawMalloc(1)`` had been called instead. The memory will not have
been initialized in any way.
.. c:function:: void* PyMem_RawCalloc(size_t nelem, size_t elsize)
Allocates *nelem* elements each whose size in bytes is *elsize* and returns
- a pointer of type :c:type:`void\*` to the allocated memory, or *NULL* if the
+ a pointer of type :c:type:`void\*` to the allocated memory, or ``NULL`` if the
request fails. The memory is initialized to zeros.
Requesting zero elements or elements of size zero bytes returns a distinct
- non-*NULL* pointer if possible, as if ``PyMem_RawCalloc(1, 1)`` had been
+ non-``NULL`` pointer if possible, as if ``PyMem_RawCalloc(1, 1)`` had been
called instead.
.. versionadded:: 3.5
Resizes the memory block pointed to by *p* to *n* bytes. The contents will
be unchanged to the minimum of the old and the new sizes.
- If *p* is *NULL*, the call is equivalent to ``PyMem_RawMalloc(n)``; else if
+ If *p* is ``NULL``, the call is equivalent to ``PyMem_RawMalloc(n)``; else if
*n* is equal to zero, the memory block is resized but is not freed, and the
- returned pointer is non-*NULL*.
+ returned pointer is non-``NULL``.
- Unless *p* is *NULL*, it must have been returned by a previous call to
+ Unless *p* is ``NULL``, it must have been returned by a previous call to
:c:func:`PyMem_RawMalloc`, :c:func:`PyMem_RawRealloc` or
:c:func:`PyMem_RawCalloc`.
- If the request fails, :c:func:`PyMem_RawRealloc` returns *NULL* and *p*
+ If the request fails, :c:func:`PyMem_RawRealloc` returns ``NULL`` and *p*
remains a valid pointer to the previous memory area.
:c:func:`PyMem_RawCalloc`. Otherwise, or if ``PyMem_RawFree(p)`` has been
called before, undefined behavior occurs.
- If *p* is *NULL*, no operation is performed.
+ If *p* is ``NULL``, no operation is performed.
.. _memoryinterface:
.. c:function:: void* PyMem_Malloc(size_t n)
Allocates *n* bytes and returns a pointer of type :c:type:`void\*` to the
- allocated memory, or *NULL* if the request fails.
+ allocated memory, or ``NULL`` if the request fails.
- Requesting zero bytes returns a distinct non-*NULL* pointer if possible, as
+ Requesting zero bytes returns a distinct non-``NULL`` pointer if possible, as
if ``PyMem_Malloc(1)`` had been called instead. The memory will not have
been initialized in any way.
.. c:function:: void* PyMem_Calloc(size_t nelem, size_t elsize)
Allocates *nelem* elements each whose size in bytes is *elsize* and returns
- a pointer of type :c:type:`void\*` to the allocated memory, or *NULL* if the
+ a pointer of type :c:type:`void\*` to the allocated memory, or ``NULL`` if the
request fails. The memory is initialized to zeros.
Requesting zero elements or elements of size zero bytes returns a distinct
- non-*NULL* pointer if possible, as if ``PyMem_Calloc(1, 1)`` had been called
+ non-``NULL`` pointer if possible, as if ``PyMem_Calloc(1, 1)`` had been called
instead.
.. versionadded:: 3.5
Resizes the memory block pointed to by *p* to *n* bytes. The contents will be
unchanged to the minimum of the old and the new sizes.
- If *p* is *NULL*, the call is equivalent to ``PyMem_Malloc(n)``; else if *n*
+ If *p* is ``NULL``, the call is equivalent to ``PyMem_Malloc(n)``; else if *n*
is equal to zero, the memory block is resized but is not freed, and the
- returned pointer is non-*NULL*.
+ returned pointer is non-``NULL``.
- Unless *p* is *NULL*, it must have been returned by a previous call to
+ Unless *p* is ``NULL``, it must have been returned by a previous call to
:c:func:`PyMem_Malloc`, :c:func:`PyMem_Realloc` or :c:func:`PyMem_Calloc`.
- If the request fails, :c:func:`PyMem_Realloc` returns *NULL* and *p* remains
+ If the request fails, :c:func:`PyMem_Realloc` returns ``NULL`` and *p* remains
a valid pointer to the previous memory area.
:c:func:`PyMem_Calloc`. Otherwise, or if ``PyMem_Free(p)`` has been called
before, undefined behavior occurs.
- If *p* is *NULL*, no operation is performed.
+ If *p* is ``NULL``, no operation is performed.
The following type-oriented macros are provided for convenience. Note that
*TYPE* refers to any C type.
Same as :c:func:`PyMem_Realloc`, but the memory block is resized to ``(n *
sizeof(TYPE))`` bytes. Returns a pointer cast to :c:type:`TYPE\*`. On return,
- *p* will be a pointer to the new memory area, or *NULL* in the event of
+ *p* will be a pointer to the new memory area, or ``NULL`` in the event of
failure.
This is a C preprocessor macro; *p* is always reassigned. Save the original
.. c:function:: void* PyObject_Malloc(size_t n)
Allocates *n* bytes and returns a pointer of type :c:type:`void\*` to the
- allocated memory, or *NULL* if the request fails.
+ allocated memory, or ``NULL`` if the request fails.
- Requesting zero bytes returns a distinct non-*NULL* pointer if possible, as
+ Requesting zero bytes returns a distinct non-``NULL`` pointer if possible, as
if ``PyObject_Malloc(1)`` had been called instead. The memory will not have
been initialized in any way.
.. c:function:: void* PyObject_Calloc(size_t nelem, size_t elsize)
Allocates *nelem* elements each whose size in bytes is *elsize* and returns
- a pointer of type :c:type:`void\*` to the allocated memory, or *NULL* if the
+ a pointer of type :c:type:`void\*` to the allocated memory, or ``NULL`` if the
request fails. The memory is initialized to zeros.
Requesting zero elements or elements of size zero bytes returns a distinct
- non-*NULL* pointer if possible, as if ``PyObject_Calloc(1, 1)`` had been called
+ non-``NULL`` pointer if possible, as if ``PyObject_Calloc(1, 1)`` had been called
instead.
.. versionadded:: 3.5
Resizes the memory block pointed to by *p* to *n* bytes. The contents will be
unchanged to the minimum of the old and the new sizes.
- If *p* is *NULL*, the call is equivalent to ``PyObject_Malloc(n)``; else if *n*
+ If *p* is ``NULL``, the call is equivalent to ``PyObject_Malloc(n)``; else if *n*
is equal to zero, the memory block is resized but is not freed, and the
- returned pointer is non-*NULL*.
+ returned pointer is non-``NULL``.
- Unless *p* is *NULL*, it must have been returned by a previous call to
+ Unless *p* is ``NULL``, it must have been returned by a previous call to
:c:func:`PyObject_Malloc`, :c:func:`PyObject_Realloc` or :c:func:`PyObject_Calloc`.
- If the request fails, :c:func:`PyObject_Realloc` returns *NULL* and *p* remains
+ If the request fails, :c:func:`PyObject_Realloc` returns ``NULL`` and *p* remains
a valid pointer to the previous memory area.
:c:func:`PyObject_Calloc`. Otherwise, or if ``PyObject_Free(p)`` has been called
before, undefined behavior occurs.
- If *p* is *NULL*, no operation is performed.
+ If *p* is ``NULL``, no operation is performed.
.. _default-memory-allocators:
.. c:function:: Py_buffer *PyMemoryView_GET_BASE(PyObject *mview)
Return either a pointer to the exporting object that the memoryview is based
- on or *NULL* if the memoryview has been created by one of the functions
+ on or ``NULL`` if the memoryview has been created by one of the functions
:c:func:`PyMemoryView_FromMemory` or :c:func:`PyMemoryView_FromBuffer`.
*mview* **must** be a memoryview instance.
.. c:function:: int PyInstanceMethod_Check(PyObject *o)
Return true if *o* is an instance method object (has type
- :c:data:`PyInstanceMethod_Type`). The parameter must not be *NULL*.
+ :c:data:`PyInstanceMethod_Type`). The parameter must not be ``NULL``.
.. c:function:: PyObject* PyInstanceMethod_New(PyObject *func)
.. c:function:: int PyMethod_Check(PyObject *o)
Return true if *o* is a method object (has type :c:data:`PyMethod_Type`). The
- parameter must not be *NULL*.
+ parameter must not be ``NULL``.
.. c:function:: PyObject* PyMethod_New(PyObject *func, PyObject *self)
Return a new method object, with *func* being any callable object and *self*
the instance the method should be bound. *func* is the function that will
- be called when the method is called. *self* must not be *NULL*.
+ be called when the method is called. *self* must not be ``NULL``.
.. c:function:: PyObject* PyMethod_Function(PyObject *meth)
Return the dictionary object that implements *module*'s namespace; this object
is the same as the :attr:`~object.__dict__` attribute of the module object.
If *module* is not a module object (or a subtype of a module object),
- :exc:`SystemError` is raised and *NULL* is returned.
+ :exc:`SystemError` is raised and ``NULL`` is returned.
It is recommended extensions use other :c:func:`PyModule_\*` and
:c:func:`PyObject_\*` functions rather than directly manipulate a module's
single: SystemError (built-in exception)
Return *module*'s :attr:`__name__` value. If the module does not provide one,
- or if it is not a string, :exc:`SystemError` is raised and *NULL* is returned.
+ or if it is not a string, :exc:`SystemError` is raised and ``NULL`` is returned.
.. versionadded:: 3.3
.. c:function:: void* PyModule_GetState(PyObject *module)
Return the "state" of the module, that is, a pointer to the block of memory
- allocated at module creation time, or *NULL*. See
+ allocated at module creation time, or ``NULL``. See
:c:member:`PyModuleDef.m_size`.
.. c:function:: PyModuleDef* PyModule_GetDef(PyObject *module)
Return a pointer to the :c:type:`PyModuleDef` struct from which the module was
- created, or *NULL* if the module wasn't created from a definition.
+ created, or ``NULL`` if the module wasn't created from a definition.
.. c:function:: PyObject* PyModule_GetFilenameObject(PyObject *module)
Return the name of the file from which *module* was loaded using *module*'s
:attr:`__file__` attribute. If this is not defined, or if it is not a
- unicode string, raise :exc:`SystemError` and return *NULL*; otherwise return
+ unicode string, raise :exc:`SystemError` and return ``NULL``; otherwise return
a reference to a Unicode object.
.. versionadded:: 3.2
.. c:member:: PyMethodDef* m_methods
A pointer to a table of module-level functions, described by
- :c:type:`PyMethodDef` values. Can be *NULL* if no functions are present.
+ :c:type:`PyMethodDef` values. Can be ``NULL`` if no functions are present.
.. c:member:: PyModuleDef_Slot* m_slots
An array of slot definitions for multi-phase initialization, terminated by
a ``{0, NULL}`` entry.
- When using single-phase initialization, *m_slots* must be *NULL*.
+ When using single-phase initialization, *m_slots* must be ``NULL``.
.. versionchanged:: 3.5
- Prior to version 3.5, this member was always set to *NULL*,
+ Prior to version 3.5, this member was always set to ``NULL``,
and was defined as:
.. c:member:: inquiry m_reload
.. c:member:: traverseproc m_traverse
A traversal function to call during GC traversal of the module object, or
- *NULL* if not needed. This function may be called before module state
+ ``NULL`` if not needed. This function may be called before module state
is allocated (:c:func:`PyModule_GetState()` may return `NULL`),
and before the :c:member:`Py_mod_exec` function is executed.
.. c:member:: inquiry m_clear
A clear function to call during GC clearing of the module object, or
- *NULL* if not needed. This function may be called before module state
+ ``NULL`` if not needed. This function may be called before module state
is allocated (:c:func:`PyModule_GetState()` may return `NULL`),
and before the :c:member:`Py_mod_exec` function is executed.
.. c:member:: freefunc m_free
- A function to call during deallocation of the module object, or *NULL* if
+ A function to call during deallocation of the module object, or ``NULL`` if
not needed. This function may be called before module state
is allocated (:c:func:`PyModule_GetState()` may return `NULL`),
and before the :c:member:`Py_mod_exec` function is executed.
Ensures a module definition is a properly initialized Python object that
correctly reports its type and reference count.
- Returns *def* cast to ``PyObject*``, or *NULL* if an error occurred.
+ Returns *def* cast to ``PyObject*``, or ``NULL`` if an error occurred.
.. versionadded:: 3.5
The function receives a :py:class:`~importlib.machinery.ModuleSpec`
instance, as defined in :PEP:`451`, and the module definition.
It should return a new module object, or set an error
- and return *NULL*.
+ and return ``NULL``.
This function should be kept minimal. In particular, it should not
call arbitrary Python code, as trying to import the same module again may
:c:type:`PyModule_Type`. Any type can be used, as long as it supports
setting and getting import-related attributes.
However, only ``PyModule_Type`` instances may be returned if the
- ``PyModuleDef`` has non-*NULL* ``m_traverse``, ``m_clear``,
+ ``PyModuleDef`` has non-``NULL`` ``m_traverse``, ``m_clear``,
``m_free``; non-zero ``m_size``; or slots other than ``Py_mod_create``.
.. c:var:: Py_mod_exec
.. c:function:: int PyModule_AddFunctions(PyObject *module, PyMethodDef *functions)
- Add the functions from the *NULL* terminated *functions* array to *module*.
+ Add the functions from the ``NULL`` terminated *functions* array to *module*.
Refer to the :c:type:`PyMethodDef` documentation for details on individual
entries (due to the lack of a shared module namespace, module level
"functions" implemented in C typically receive the module as their first
Add a string constant to *module* as *name*. This convenience function can be
used from the module's initialization function. The string *value* must be
- *NULL*-terminated. Return ``-1`` on error, ``0`` on success.
+ ``NULL``-terminated. Return ``-1`` on error, ``0`` on success.
.. c:function:: int PyModule_AddIntMacro(PyObject *module, macro)
Returns the module object that was created from *def* for the current interpreter.
This method requires that the module object has been attached to the interpreter state with
:c:func:`PyState_AddModule` beforehand. In case the corresponding module object is not
- found or has not been attached to the interpreter state yet, it returns *NULL*.
+ found or has not been attached to the interpreter state yet, it returns ``NULL``.
.. c:function:: int PyState_AddModule(PyObject *module, PyModuleDef *def)
.. c:function:: PyObject* PyNumber_Add(PyObject *o1, PyObject *o2)
- Returns the result of adding *o1* and *o2*, or *NULL* on failure. This is the
+ Returns the result of adding *o1* and *o2*, or ``NULL`` on failure. This is the
equivalent of the Python expression ``o1 + o2``.
.. c:function:: PyObject* PyNumber_Subtract(PyObject *o1, PyObject *o2)
- Returns the result of subtracting *o2* from *o1*, or *NULL* on failure. This is
+ Returns the result of subtracting *o2* from *o1*, or ``NULL`` on failure. This is
the equivalent of the Python expression ``o1 - o2``.
.. c:function:: PyObject* PyNumber_Multiply(PyObject *o1, PyObject *o2)
- Returns the result of multiplying *o1* and *o2*, or *NULL* on failure. This is
+ Returns the result of multiplying *o1* and *o2*, or ``NULL`` on failure. This is
the equivalent of the Python expression ``o1 * o2``.
.. c:function:: PyObject* PyNumber_MatrixMultiply(PyObject *o1, PyObject *o2)
- Returns the result of matrix multiplication on *o1* and *o2*, or *NULL* on
+ Returns the result of matrix multiplication on *o1* and *o2*, or ``NULL`` on
failure. This is the equivalent of the Python expression ``o1 @ o2``.
.. versionadded:: 3.5
.. c:function:: PyObject* PyNumber_FloorDivide(PyObject *o1, PyObject *o2)
- Return the floor of *o1* divided by *o2*, or *NULL* on failure. This is
+ Return the floor of *o1* divided by *o2*, or ``NULL`` on failure. This is
equivalent to the "classic" division of integers.
.. c:function:: PyObject* PyNumber_TrueDivide(PyObject *o1, PyObject *o2)
Return a reasonable approximation for the mathematical value of *o1* divided by
- *o2*, or *NULL* on failure. The return value is "approximate" because binary
+ *o2*, or ``NULL`` on failure. The return value is "approximate" because binary
floating point numbers are approximate; it is not possible to represent all real
numbers in base two. This function can return a floating point value when
passed two integers.
.. c:function:: PyObject* PyNumber_Remainder(PyObject *o1, PyObject *o2)
- Returns the remainder of dividing *o1* by *o2*, or *NULL* on failure. This is
+ Returns the remainder of dividing *o1* by *o2*, or ``NULL`` on failure. This is
the equivalent of the Python expression ``o1 % o2``.
.. index:: builtin: divmod
- See the built-in function :func:`divmod`. Returns *NULL* on failure. This is
+ See the built-in function :func:`divmod`. Returns ``NULL`` on failure. This is
the equivalent of the Python expression ``divmod(o1, o2)``.
.. index:: builtin: pow
- See the built-in function :func:`pow`. Returns *NULL* on failure. This is the
+ See the built-in function :func:`pow`. Returns ``NULL`` on failure. This is the
equivalent of the Python expression ``pow(o1, o2, o3)``, where *o3* is optional.
- If *o3* is to be ignored, pass :c:data:`Py_None` in its place (passing *NULL* for
+ If *o3* is to be ignored, pass :c:data:`Py_None` in its place (passing ``NULL`` for
*o3* would cause an illegal memory access).
.. c:function:: PyObject* PyNumber_Negative(PyObject *o)
- Returns the negation of *o* on success, or *NULL* on failure. This is the
+ Returns the negation of *o* on success, or ``NULL`` on failure. This is the
equivalent of the Python expression ``-o``.
.. c:function:: PyObject* PyNumber_Positive(PyObject *o)
- Returns *o* on success, or *NULL* on failure. This is the equivalent of the
+ Returns *o* on success, or ``NULL`` on failure. This is the equivalent of the
Python expression ``+o``.
.. index:: builtin: abs
- Returns the absolute value of *o*, or *NULL* on failure. This is the equivalent
+ Returns the absolute value of *o*, or ``NULL`` on failure. This is the equivalent
of the Python expression ``abs(o)``.
.. c:function:: PyObject* PyNumber_Invert(PyObject *o)
- Returns the bitwise negation of *o* on success, or *NULL* on failure. This is
+ Returns the bitwise negation of *o* on success, or ``NULL`` on failure. This is
the equivalent of the Python expression ``~o``.
.. c:function:: PyObject* PyNumber_Lshift(PyObject *o1, PyObject *o2)
- Returns the result of left shifting *o1* by *o2* on success, or *NULL* on
+ Returns the result of left shifting *o1* by *o2* on success, or ``NULL`` on
failure. This is the equivalent of the Python expression ``o1 << o2``.
.. c:function:: PyObject* PyNumber_Rshift(PyObject *o1, PyObject *o2)
- Returns the result of right shifting *o1* by *o2* on success, or *NULL* on
+ Returns the result of right shifting *o1* by *o2* on success, or ``NULL`` on
failure. This is the equivalent of the Python expression ``o1 >> o2``.
.. c:function:: PyObject* PyNumber_And(PyObject *o1, PyObject *o2)
- Returns the "bitwise and" of *o1* and *o2* on success and *NULL* on failure.
+ Returns the "bitwise and" of *o1* and *o2* on success and ``NULL`` on failure.
This is the equivalent of the Python expression ``o1 & o2``.
.. c:function:: PyObject* PyNumber_Xor(PyObject *o1, PyObject *o2)
- Returns the "bitwise exclusive or" of *o1* by *o2* on success, or *NULL* on
+ Returns the "bitwise exclusive or" of *o1* by *o2* on success, or ``NULL`` on
failure. This is the equivalent of the Python expression ``o1 ^ o2``.
.. c:function:: PyObject* PyNumber_Or(PyObject *o1, PyObject *o2)
- Returns the "bitwise or" of *o1* and *o2* on success, or *NULL* on failure.
+ Returns the "bitwise or" of *o1* and *o2* on success, or ``NULL`` on failure.
This is the equivalent of the Python expression ``o1 | o2``.
.. c:function:: PyObject* PyNumber_InPlaceAdd(PyObject *o1, PyObject *o2)
- Returns the result of adding *o1* and *o2*, or *NULL* on failure. The operation
+ Returns the result of adding *o1* and *o2*, or ``NULL`` on failure. The operation
is done *in-place* when *o1* supports it. This is the equivalent of the Python
statement ``o1 += o2``.
.. c:function:: PyObject* PyNumber_InPlaceSubtract(PyObject *o1, PyObject *o2)
- Returns the result of subtracting *o2* from *o1*, or *NULL* on failure. The
+ Returns the result of subtracting *o2* from *o1*, or ``NULL`` on failure. The
operation is done *in-place* when *o1* supports it. This is the equivalent of
the Python statement ``o1 -= o2``.
.. c:function:: PyObject* PyNumber_InPlaceMultiply(PyObject *o1, PyObject *o2)
- Returns the result of multiplying *o1* and *o2*, or *NULL* on failure. The
+ Returns the result of multiplying *o1* and *o2*, or ``NULL`` on failure. The
operation is done *in-place* when *o1* supports it. This is the equivalent of
the Python statement ``o1 *= o2``.
.. c:function:: PyObject* PyNumber_InPlaceMatrixMultiply(PyObject *o1, PyObject *o2)
- Returns the result of matrix multiplication on *o1* and *o2*, or *NULL* on
+ Returns the result of matrix multiplication on *o1* and *o2*, or ``NULL`` on
failure. The operation is done *in-place* when *o1* supports it. This is
the equivalent of the Python statement ``o1 @= o2``.
.. c:function:: PyObject* PyNumber_InPlaceFloorDivide(PyObject *o1, PyObject *o2)
- Returns the mathematical floor of dividing *o1* by *o2*, or *NULL* on failure.
+ Returns the mathematical floor of dividing *o1* by *o2*, or ``NULL`` on failure.
The operation is done *in-place* when *o1* supports it. This is the equivalent
of the Python statement ``o1 //= o2``.
.. c:function:: PyObject* PyNumber_InPlaceTrueDivide(PyObject *o1, PyObject *o2)
Return a reasonable approximation for the mathematical value of *o1* divided by
- *o2*, or *NULL* on failure. The return value is "approximate" because binary
+ *o2*, or ``NULL`` on failure. The return value is "approximate" because binary
floating point numbers are approximate; it is not possible to represent all real
numbers in base two. This function can return a floating point value when
passed two integers. The operation is done *in-place* when *o1* supports it.
.. c:function:: PyObject* PyNumber_InPlaceRemainder(PyObject *o1, PyObject *o2)
- Returns the remainder of dividing *o1* by *o2*, or *NULL* on failure. The
+ Returns the remainder of dividing *o1* by *o2*, or ``NULL`` on failure. The
operation is done *in-place* when *o1* supports it. This is the equivalent of
the Python statement ``o1 %= o2``.
.. index:: builtin: pow
- See the built-in function :func:`pow`. Returns *NULL* on failure. The operation
+ See the built-in function :func:`pow`. Returns ``NULL`` on failure. The operation
is done *in-place* when *o1* supports it. This is the equivalent of the Python
statement ``o1 **= o2`` when o3 is :c:data:`Py_None`, or an in-place variant of
``pow(o1, o2, o3)`` otherwise. If *o3* is to be ignored, pass :c:data:`Py_None`
- in its place (passing *NULL* for *o3* would cause an illegal memory access).
+ in its place (passing ``NULL`` for *o3* would cause an illegal memory access).
.. c:function:: PyObject* PyNumber_InPlaceLshift(PyObject *o1, PyObject *o2)
- Returns the result of left shifting *o1* by *o2* on success, or *NULL* on
+ Returns the result of left shifting *o1* by *o2* on success, or ``NULL`` on
failure. The operation is done *in-place* when *o1* supports it. This is the
equivalent of the Python statement ``o1 <<= o2``.
.. c:function:: PyObject* PyNumber_InPlaceRshift(PyObject *o1, PyObject *o2)
- Returns the result of right shifting *o1* by *o2* on success, or *NULL* on
+ Returns the result of right shifting *o1* by *o2* on success, or ``NULL`` on
failure. The operation is done *in-place* when *o1* supports it. This is the
equivalent of the Python statement ``o1 >>= o2``.
.. c:function:: PyObject* PyNumber_InPlaceAnd(PyObject *o1, PyObject *o2)
- Returns the "bitwise and" of *o1* and *o2* on success and *NULL* on failure. The
+ Returns the "bitwise and" of *o1* and *o2* on success and ``NULL`` on failure. The
operation is done *in-place* when *o1* supports it. This is the equivalent of
the Python statement ``o1 &= o2``.
.. c:function:: PyObject* PyNumber_InPlaceXor(PyObject *o1, PyObject *o2)
- Returns the "bitwise exclusive or" of *o1* by *o2* on success, or *NULL* on
+ Returns the "bitwise exclusive or" of *o1* by *o2* on success, or ``NULL`` on
failure. The operation is done *in-place* when *o1* supports it. This is the
equivalent of the Python statement ``o1 ^= o2``.
.. c:function:: PyObject* PyNumber_InPlaceOr(PyObject *o1, PyObject *o2)
- Returns the "bitwise or" of *o1* and *o2* on success, or *NULL* on failure. The
+ Returns the "bitwise or" of *o1* and *o2* on success, or ``NULL`` on failure. The
operation is done *in-place* when *o1* supports it. This is the equivalent of
the Python statement ``o1 |= o2``.
.. index:: builtin: int
- Returns the *o* converted to an integer object on success, or *NULL* on
+ Returns the *o* converted to an integer object on success, or ``NULL`` on
failure. This is the equivalent of the Python expression ``int(o)``.
.. index:: builtin: float
- Returns the *o* converted to a float object on success, or *NULL* on failure.
+ Returns the *o* converted to a float object on success, or ``NULL`` on failure.
This is the equivalent of the Python expression ``float(o)``.
.. c:function:: PyObject* PyNumber_Index(PyObject *o)
- Returns the *o* converted to a Python int on success or *NULL* with a
+ Returns the *o* converted to a Python int on success or ``NULL`` with a
:exc:`TypeError` exception raised on failure.
If *o* can be converted to a Python int but the attempt to
convert to a Py_ssize_t value would raise an :exc:`OverflowError`, then the
*exc* argument is the type of exception that will be raised (usually
- :exc:`IndexError` or :exc:`OverflowError`). If *exc* is *NULL*, then the
+ :exc:`IndexError` or :exc:`OverflowError`). If *exc* is ``NULL``, then the
exception is cleared and the value is clipped to *PY_SSIZE_T_MIN* for a negative
integer or *PY_SSIZE_T_MAX* for a positive integer.
.. c:function:: PyObject* PyObject_GetAttr(PyObject *o, PyObject *attr_name)
Retrieve an attribute named *attr_name* from object *o*. Returns the attribute
- value on success, or *NULL* on failure. This is the equivalent of the Python
+ value on success, or ``NULL`` on failure. This is the equivalent of the Python
expression ``o.attr_name``.
.. c:function:: PyObject* PyObject_GetAttrString(PyObject *o, const char *attr_name)
Retrieve an attribute named *attr_name* from object *o*. Returns the attribute
- value on success, or *NULL* on failure. This is the equivalent of the Python
+ value on success, or ``NULL`` on failure. This is the equivalent of the Python
expression ``o.attr_name``.
return ``0`` on success. This is the equivalent of the Python statement
``o.attr_name = v``.
- If *v* is *NULL*, the attribute is deleted, however this feature is
+ If *v* is ``NULL``, the attribute is deleted, however this feature is
deprecated in favour of using :c:func:`PyObject_DelAttr`.
return ``0`` on success. This is the equivalent of the Python statement
``o.attr_name = v``.
- If *v* is *NULL*, the attribute is deleted, however this feature is
+ If *v* is ``NULL``, the attribute is deleted, however this feature is
deprecated in favour of using :c:func:`PyObject_DelAttrString`.
:const:`Py_NE`, :const:`Py_GT`, or :const:`Py_GE`, corresponding to ``<``,
``<=``, ``==``, ``!=``, ``>``, or ``>=`` respectively. This is the equivalent of
the Python expression ``o1 op o2``, where ``op`` is the operator corresponding
- to *opid*. Returns the value of the comparison on success, or *NULL* on failure.
+ to *opid*. Returns the value of the comparison on success, or ``NULL`` on failure.
.. c:function:: int PyObject_RichCompareBool(PyObject *o1, PyObject *o2, int opid)
.. index:: builtin: repr
Compute a string representation of object *o*. Returns the string
- representation on success, *NULL* on failure. This is the equivalent of the
+ representation on success, ``NULL`` on failure. This is the equivalent of the
Python expression ``repr(o)``. Called by the :func:`repr` built-in function.
.. versionchanged:: 3.4
.. c:function:: PyObject* PyObject_Str(PyObject *o)
Compute a string representation of object *o*. Returns the string
- representation on success, *NULL* on failure. This is the equivalent of the
+ representation on success, ``NULL`` on failure. This is the equivalent of the
Python expression ``str(o)``. Called by the :func:`str` built-in function
and, therefore, by the :func:`print` function.
.. index:: builtin: bytes
- Compute a bytes representation of object *o*. *NULL* is returned on
+ Compute a bytes representation of object *o*. ``NULL`` is returned on
failure and a bytes object on success. This is equivalent to the Python
expression ``bytes(o)``, when *o* is not an integer. Unlike ``bytes(o)``,
a TypeError is raised when *o* is an integer instead of a zero-initialized
Call a callable Python object *callable*, with arguments given by the
tuple *args*, and named arguments given by the dictionary *kwargs*.
- *args* must not be *NULL*, use an empty tuple if no arguments are needed.
- If no named arguments are needed, *kwargs* can be *NULL*.
+ *args* must not be ``NULL``, use an empty tuple if no arguments are needed.
+ If no named arguments are needed, *kwargs* can be ``NULL``.
Return the result of the call on success, or raise an exception and return
- *NULL* on failure.
+ ``NULL`` on failure.
This is the equivalent of the Python expression:
``callable(*args, **kwargs)``.
.. c:function:: PyObject* PyObject_CallObject(PyObject *callable, PyObject *args)
Call a callable Python object *callable*, with arguments given by the
- tuple *args*. If no arguments are needed, then *args* can be *NULL*.
+ tuple *args*. If no arguments are needed, then *args* can be ``NULL``.
Return the result of the call on success, or raise an exception and return
- *NULL* on failure.
+ ``NULL`` on failure.
This is the equivalent of the Python expression: ``callable(*args)``.
Call a callable Python object *callable*, with a variable number of C arguments.
The C arguments are described using a :c:func:`Py_BuildValue` style format
- string. The format can be *NULL*, indicating that no arguments are provided.
+ string. The format can be ``NULL``, indicating that no arguments are provided.
Return the result of the call on success, or raise an exception and return
- *NULL* on failure.
+ ``NULL`` on failure.
This is the equivalent of the Python expression: ``callable(*args)``.
arguments. The C arguments are described by a :c:func:`Py_BuildValue` format
string that should produce a tuple.
- The format can be *NULL*, indicating that no arguments are provided.
+ The format can be ``NULL``, indicating that no arguments are provided.
Return the result of the call on success, or raise an exception and return
- *NULL* on failure.
+ ``NULL`` on failure.
This is the equivalent of the Python expression:
``obj.name(arg1, arg2, ...)``.
Call a callable Python object *callable*, with a variable number of
:c:type:`PyObject\*` arguments. The arguments are provided as a variable number
- of parameters followed by *NULL*.
+ of parameters followed by ``NULL``.
Return the result of the call on success, or raise an exception and return
- *NULL* on failure.
+ ``NULL`` on failure.
This is the equivalent of the Python expression:
``callable(arg1, arg2, ...)``.
Calls a method of the Python object *obj*, where the name of the method is given as a
Python string object in *name*. It is called with a variable number of
:c:type:`PyObject\*` arguments. The arguments are provided as a variable number
- of parameters followed by *NULL*.
+ of parameters followed by ``NULL``.
Return the result of the call on success, or raise an exception and return
- *NULL* on failure.
+ ``NULL`` on failure.
.. c:function:: Py_hash_t PyObject_Hash(PyObject *o)
.. index:: builtin: type
- When *o* is non-*NULL*, returns a type object corresponding to the object type
- of object *o*. On failure, raises :exc:`SystemError` and returns *NULL*. This
+ When *o* is non-``NULL``, returns a type object corresponding to the object type
+ of object *o*. On failure, raises :exc:`SystemError` and returns ``NULL``. This
is equivalent to the Python expression ``type(o)``. This function increments the
reference count of the return value. There's really no reason to use this
function instead of the common expression ``o->ob_type``, which returns a
.. c:function:: int PyObject_TypeCheck(PyObject *o, PyTypeObject *type)
Return true if the object *o* is of type *type* or a subtype of *type*. Both
- parameters must be non-*NULL*.
+ parameters must be non-``NULL``.
.. c:function:: Py_ssize_t PyObject_Size(PyObject *o)
.. c:function:: PyObject* PyObject_GetItem(PyObject *o, PyObject *key)
- Return element of *o* corresponding to the object *key* or *NULL* on failure.
+ Return element of *o* corresponding to the object *key* or ``NULL`` on failure.
This is the equivalent of the Python expression ``o[key]``.
.. c:function:: PyObject* PyObject_Dir(PyObject *o)
This is equivalent to the Python expression ``dir(o)``, returning a (possibly
- empty) list of strings appropriate for the object argument, or *NULL* if there
- was an error. If the argument is *NULL*, this is like the Python ``dir()``,
+ empty) list of strings appropriate for the object argument, or ``NULL`` if there
+ was an error. If the argument is ``NULL``, this is like the Python ``dir()``,
returning the names of the current locals; in this case, if no execution frame
- is active then *NULL* is returned but :c:func:`PyErr_Occurred` will return false.
+ is active then ``NULL`` is returned but :c:func:`PyErr_Occurred` will return false.
.. c:function:: PyObject* PyObject_GetIter(PyObject *o)
This is equivalent to the Python expression ``iter(o)``. It returns a new
iterator for the object argument, or the object itself if the object is already
- an iterator. Raises :exc:`TypeError` and returns *NULL* if the object cannot be
+ an iterator. Raises :exc:`TypeError` and returns ``NULL`` if the object cannot be
iterated.
.. c:function:: void Py_INCREF(PyObject *o)
- Increment the reference count for object *o*. The object must not be *NULL*; if
- you aren't sure that it isn't *NULL*, use :c:func:`Py_XINCREF`.
+ Increment the reference count for object *o*. The object must not be ``NULL``; if
+ you aren't sure that it isn't ``NULL``, use :c:func:`Py_XINCREF`.
.. c:function:: void Py_XINCREF(PyObject *o)
- Increment the reference count for object *o*. The object may be *NULL*, in
+ Increment the reference count for object *o*. The object may be ``NULL``, in
which case the macro has no effect.
.. c:function:: void Py_DECREF(PyObject *o)
- Decrement the reference count for object *o*. The object must not be *NULL*; if
- you aren't sure that it isn't *NULL*, use :c:func:`Py_XDECREF`. If the reference
+ Decrement the reference count for object *o*. The object must not be ``NULL``; if
+ you aren't sure that it isn't ``NULL``, use :c:func:`Py_XDECREF`. If the reference
count reaches zero, the object's type's deallocation function (which must not be
- *NULL*) is invoked.
+ ``NULL``) is invoked.
.. warning::
.. c:function:: void Py_XDECREF(PyObject *o)
- Decrement the reference count for object *o*. The object may be *NULL*, in
+ Decrement the reference count for object *o*. The object may be ``NULL``, in
which case the macro has no effect; otherwise the effect is the same as for
:c:func:`Py_DECREF`, and the same warning applies.
.. c:function:: void Py_CLEAR(PyObject *o)
- Decrement the reference count for object *o*. The object may be *NULL*, in
+ Decrement the reference count for object *o*. The object may be ``NULL``, in
which case the macro has no effect; otherwise the effect is the same as for
- :c:func:`Py_DECREF`, except that the argument is also set to *NULL*. The warning
+ :c:func:`Py_DECREF`, except that the argument is also set to ``NULL``. The warning
for :c:func:`Py_DECREF` does not apply with respect to the object passed because
- the macro carefully uses a temporary variable and sets the argument to *NULL*
+ the macro carefully uses a temporary variable and sets the argument to ``NULL``
before decrementing its reference count.
It is a good idea to use this macro whenever decrementing the value of a
.. c:function:: PyObject* PyEval_GetLocals()
Return a dictionary of the local variables in the current execution frame,
- or *NULL* if no frame is currently executing.
+ or ``NULL`` if no frame is currently executing.
.. c:function:: PyObject* PyEval_GetGlobals()
Return a dictionary of the global variables in the current execution frame,
- or *NULL* if no frame is currently executing.
+ or ``NULL`` if no frame is currently executing.
.. c:function:: PyFrameObject* PyEval_GetFrame()
- Return the current thread state's frame, which is *NULL* if no frame is
+ Return the current thread state's frame, which is ``NULL`` if no frame is
currently executing.
.. c:function:: PyObject* PySequence_Concat(PyObject *o1, PyObject *o2)
- Return the concatenation of *o1* and *o2* on success, and *NULL* on failure.
+ Return the concatenation of *o1* and *o2* on success, and ``NULL`` on failure.
This is the equivalent of the Python expression ``o1 + o2``.
.. c:function:: PyObject* PySequence_Repeat(PyObject *o, Py_ssize_t count)
- Return the result of repeating sequence object *o* *count* times, or *NULL* on
+ Return the result of repeating sequence object *o* *count* times, or ``NULL`` on
failure. This is the equivalent of the Python expression ``o * count``.
.. c:function:: PyObject* PySequence_InPlaceConcat(PyObject *o1, PyObject *o2)
- Return the concatenation of *o1* and *o2* on success, and *NULL* on failure.
+ Return the concatenation of *o1* and *o2* on success, and ``NULL`` on failure.
The operation is done *in-place* when *o1* supports it. This is the equivalent
of the Python expression ``o1 += o2``.
.. c:function:: PyObject* PySequence_InPlaceRepeat(PyObject *o, Py_ssize_t count)
- Return the result of repeating sequence object *o* *count* times, or *NULL* on
+ Return the result of repeating sequence object *o* *count* times, or ``NULL`` on
failure. The operation is done *in-place* when *o* supports it. This is the
equivalent of the Python expression ``o *= count``.
.. c:function:: PyObject* PySequence_GetItem(PyObject *o, Py_ssize_t i)
- Return the *i*\ th element of *o*, or *NULL* on failure. This is the equivalent of
+ Return the *i*\ th element of *o*, or ``NULL`` on failure. This is the equivalent of
the Python expression ``o[i]``.
.. c:function:: PyObject* PySequence_GetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2)
- Return the slice of sequence object *o* between *i1* and *i2*, or *NULL* on
+ Return the slice of sequence object *o* between *i1* and *i2*, or ``NULL`` on
failure. This is the equivalent of the Python expression ``o[i1:i2]``.
is the equivalent of the Python statement ``o[i] = v``. This function *does
not* steal a reference to *v*.
- If *v* is *NULL*, the element is deleted, however this feature is
+ If *v* is ``NULL``, the element is deleted, however this feature is
deprecated in favour of using :c:func:`PySequence_DelItem`.
.. c:function:: PyObject* PySequence_List(PyObject *o)
Return a list object with the same contents as the sequence or iterable *o*,
- or *NULL* on failure. The returned list is guaranteed to be new. This is
+ or ``NULL`` on failure. The returned list is guaranteed to be new. This is
equivalent to the Python expression ``list(o)``.
.. index:: builtin: tuple
Return a tuple object with the same contents as the sequence or iterable *o*,
- or *NULL* on failure. If *o* is a tuple, a new reference will be returned,
+ or ``NULL`` on failure. If *o* is a tuple, a new reference will be returned,
otherwise a tuple will be constructed with the appropriate contents. This is
equivalent to the Python expression ``tuple(o)``.
Return the sequence or iterable *o* as an object usable by the other
``PySequence_Fast*`` family of functions. If the object is not a sequence or
iterable, raises :exc:`TypeError` with *m* as the message text. Returns
- *NULL* on failure.
+ ``NULL`` on failure.
The ``PySequence_Fast*`` functions are thus named because they assume
*o* is a :c:type:`PyTupleObject` or a :c:type:`PyListObject` and access
.. c:function:: Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o)
Returns the length of *o*, assuming that *o* was returned by
- :c:func:`PySequence_Fast` and that *o* is not *NULL*. The size can also be
+ :c:func:`PySequence_Fast` and that *o* is not ``NULL``. The size can also be
gotten by calling :c:func:`PySequence_Size` on *o*, but
:c:func:`PySequence_Fast_GET_SIZE` is faster because it can assume *o* is a
list or tuple.
.. c:function:: PyObject* PySequence_Fast_GET_ITEM(PyObject *o, Py_ssize_t i)
Return the *i*\ th element of *o*, assuming that *o* was returned by
- :c:func:`PySequence_Fast`, *o* is not *NULL*, and that *i* is within bounds.
+ :c:func:`PySequence_Fast`, *o* is not ``NULL``, and that *i* is within bounds.
.. c:function:: PyObject** PySequence_Fast_ITEMS(PyObject *o)
Return the underlying array of PyObject pointers. Assumes that *o* was returned
- by :c:func:`PySequence_Fast` and *o* is not *NULL*.
+ by :c:func:`PySequence_Fast` and *o* is not ``NULL``.
Note, if a list gets resized, the reallocation may relocate the items array.
So, only use the underlying array pointer in contexts where the sequence
.. c:function:: PyObject* PySequence_ITEM(PyObject *o, Py_ssize_t i)
- Return the *i*\ th element of *o* or *NULL* on failure. Faster form of
+ Return the *i*\ th element of *o* or ``NULL`` on failure. Faster form of
:c:func:`PySequence_GetItem` but without checking that
:c:func:`PySequence_Check` on *o* is true and without adjustment for negative
indices.
.. c:function:: PyObject* PySet_New(PyObject *iterable)
Return a new :class:`set` containing objects returned by the *iterable*. The
- *iterable* may be *NULL* to create a new empty set. Return the new set on
- success or *NULL* on failure. Raise :exc:`TypeError` if *iterable* is not
+ *iterable* may be ``NULL`` to create a new empty set. Return the new set on
+ success or ``NULL`` on failure. Raise :exc:`TypeError` if *iterable* is not
actually iterable. The constructor is also useful for copying a set
(``c=set(s)``).
.. c:function:: PyObject* PyFrozenSet_New(PyObject *iterable)
Return a new :class:`frozenset` containing objects returned by the *iterable*.
- The *iterable* may be *NULL* to create a new empty frozenset. Return the new
- set on success or *NULL* on failure. Raise :exc:`TypeError` if *iterable* is
+ The *iterable* may be ``NULL`` to create a new empty frozenset. Return the new
+ set on success or ``NULL`` on failure. Raise :exc:`TypeError` if *iterable* is
not actually iterable.
.. c:function:: PyObject* PySet_Pop(PyObject *set)
Return a new reference to an arbitrary object in the *set*, and removes the
- object from the *set*. Return *NULL* on failure. Raise :exc:`KeyError` if the
+ object from the *set*. Return ``NULL`` on failure. Raise :exc:`KeyError` if the
set is empty. Raise a :exc:`SystemError` if *set* is not an instance of
:class:`set` or its subtype.
.. c:function:: int PySlice_Check(PyObject *ob)
- Return true if *ob* is a slice object; *ob* must not be *NULL*.
+ Return true if *ob* is a slice object; *ob* must not be ``NULL``.
.. c:function:: PyObject* PySlice_New(PyObject *start, PyObject *stop, PyObject *step)
Return a new slice object with the given values. The *start*, *stop*, and
*step* parameters are used as the values of the slice object attributes of
- the same names. Any of the values may be *NULL*, in which case the
- ``None`` will be used for the corresponding attribute. Return *NULL* if
+ the same names. Any of the values may be ``NULL``, in which case the
+ ``None`` will be used for the corresponding attribute. Return ``NULL`` if
the new object could not be allocated.
Type of the functions used to implement most Python callables in C.
Functions of this type take two :c:type:`PyObject\*` parameters and return
- one such value. If the return value is *NULL*, an exception shall have
- been set. If not *NULL*, the return value is interpreted as the return
+ one such value. If the return value is ``NULL``, an exception shall have
+ been set. If not ``NULL``, the return value is interpreted as the return
value of the function as exposed in Python. The function must return a new
reference.
Methods with these flags must be of type :c:type:`PyCFunctionWithKeywords`.
The function expects three parameters: *self*, *args*, *kwargs* where
- *kwargs* is a dictionary of all the keyword arguments or possibly *NULL*
+ *kwargs* is a dictionary of all the keyword arguments or possibly ``NULL``
if there are no keyword arguments. The parameters are typically processed
using :c:func:`PyArg_ParseTupleAndKeywords`.
Keyword arguments are passed the same way as in the vectorcall protocol:
there is an additional fourth :c:type:`PyObject\*` parameter
which is a tuple representing the names of the keyword arguments
- or possibly *NULL* if there are no keywords. The values of the keyword
+ or possibly ``NULL`` if there are no keywords. The values of the keyword
arguments are stored in the *args* array, after the positional arguments.
This is not part of the :ref:`limited API <stable>`.
they are listed with the :const:`METH_NOARGS` flag. They need to be of type
:c:type:`PyCFunction`. The first parameter is typically named *self* and will
hold a reference to the module or object instance. In all cases the second
- parameter will be *NULL*.
+ parameter will be ``NULL``.
.. data:: METH_O
.. index:: builtin: staticmethod
- The method will be passed *NULL* as the first parameter rather than an
+ The method will be passed ``NULL`` as the first parameter rather than an
instance of the type. This is used to create *static methods*, similar to
what is created when using the :func:`staticmethod` built-in function.
=============== ==================
:c:macro:`T_OBJECT` and :c:macro:`T_OBJECT_EX` differ in that
- :c:macro:`T_OBJECT` returns ``None`` if the member is *NULL* and
+ :c:macro:`T_OBJECT` returns ``None`` if the member is ``NULL`` and
:c:macro:`T_OBJECT_EX` raises an :exc:`AttributeError`. Try to use
:c:macro:`T_OBJECT_EX` over :c:macro:`T_OBJECT` because :c:macro:`T_OBJECT_EX`
handles use of the :keyword:`del` statement on that attribute more correctly
read-only access. Using :c:macro:`T_STRING` for :attr:`type` implies
:c:macro:`READONLY`. :c:macro:`T_STRING` data is interpreted as UTF-8.
Only :c:macro:`T_OBJECT` and :c:macro:`T_OBJECT_EX`
- members can be deleted. (They are set to *NULL*).
+ members can be deleted. (They are set to ``NULL``).
.. c:type:: PyGetSetDef
typedef PyObject *(*getter)(PyObject *, void *);
- It should return a new reference on success or *NULL* with a set exception
+ It should return a new reference on success or ``NULL`` with a set exception
on failure.
``set`` functions take two :c:type:`PyObject\*` parameters (the instance and
typedef int (*setter)(PyObject *, PyObject *, void *);
- In case the attribute should be deleted the second parameter is *NULL*.
+ In case the attribute should be deleted the second parameter is ``NULL``.
Should return ``0`` on success or ``-1`` with a set exception on failure.
Return true (nonzero) if the standard I/O file *fp* with name *filename* is
deemed interactive. This is the case for files for which ``isatty(fileno(fp))``
is true. If the global flag :c:data:`Py_InteractiveFlag` is true, this function
- also returns true if the *filename* pointer is *NULL* or if the name is equal to
+ also returns true if the *filename* pointer is ``NULL`` or if the name is equal to
one of the strings ``'<stdin>'`` or ``'???'``.
.. c:function:: PyObject *PySys_GetObject(const char *name)
- Return the object *name* from the :mod:`sys` module or *NULL* if it does
+ Return the object *name* from the :mod:`sys` module or ``NULL`` if it does
not exist, without setting an exception.
.. c:function:: int PySys_SetObject(const char *name, PyObject *v)
- Set *name* in the :mod:`sys` module to *v* unless *v* is *NULL*, in which
+ Set *name* in the :mod:`sys` module to *v* unless *v* is ``NULL``, in which
case *name* is deleted from the sys module. Returns ``0`` on success, ``-1``
on error.
.. c:function:: PyObject *PySys_GetXOptions()
Return the current dictionary of :option:`-X` options, similarly to
- :data:`sys._xoptions`. On error, *NULL* is returned and an exception is
+ :data:`sys._xoptions`. On error, ``NULL`` is returned and an exception is
set.
.. versionadded:: 3.2
.. c:function:: PyObject* PyTuple_New(Py_ssize_t len)
- Return a new tuple object of size *len*, or *NULL* on failure.
+ Return a new tuple object of size *len*, or ``NULL`` on failure.
.. c:function:: PyObject* PyTuple_Pack(Py_ssize_t n, ...)
- Return a new tuple object of size *n*, or *NULL* on failure. The tuple values
+ Return a new tuple object of size *n*, or ``NULL`` on failure. The tuple values
are initialized to the subsequent *n* C arguments pointing to Python objects.
``PyTuple_Pack(2, a, b)`` is equivalent to ``Py_BuildValue("(OO)", a, b)``.
.. c:function:: Py_ssize_t PyTuple_GET_SIZE(PyObject *p)
- Return the size of the tuple *p*, which must be non-*NULL* and point to a tuple;
+ Return the size of the tuple *p*, which must be non-``NULL`` and point to a tuple;
no error checking is performed.
.. c:function:: PyObject* PyTuple_GetItem(PyObject *p, Py_ssize_t pos)
Return the object at position *pos* in the tuple pointed to by *p*. If *pos* is
- out of bounds, return *NULL* and set an :exc:`IndexError` exception.
+ out of bounds, return ``NULL`` and set an :exc:`IndexError` exception.
.. c:function:: PyObject* PyTuple_GET_ITEM(PyObject *p, Py_ssize_t pos)
.. c:function:: PyObject* PyTuple_GetSlice(PyObject *p, Py_ssize_t low, Py_ssize_t high)
Return the slice of the tuple pointed to by *p* between *low* and *high*,
- or *NULL* on failure. This is the equivalent of the Python expression
+ or ``NULL`` on failure. This is the equivalent of the Python expression
``p[low:high]``. Indexing from the end of the list is not supported.
only more efficiently. Returns ``0`` on success. Client code should never
assume that the resulting value of ``*p`` will be the same as before calling
this function. If the object referenced by ``*p`` is replaced, the original
- ``*p`` is destroyed. On failure, returns ``-1`` and sets ``*p`` to *NULL*, and
+ ``*p`` is destroyed. On failure, returns ``-1`` and sets ``*p`` to ``NULL``, and
raises :exc:`MemoryError` or :exc:`SystemError`.
Contains the meta information of a struct sequence type to create.
- +-------------------+------------------------------+------------------------------------+
- | Field | C Type | Meaning |
- +===================+==============================+====================================+
- | ``name`` | ``const char *`` | name of the struct sequence type |
- +-------------------+------------------------------+------------------------------------+
- | ``doc`` | ``const char *`` | pointer to docstring for the type |
- | | | or NULL to omit |
- +-------------------+------------------------------+------------------------------------+
- | ``fields`` | ``PyStructSequence_Field *`` | pointer to *NULL*-terminated array |
- | | | with field names of the new type |
- +-------------------+------------------------------+------------------------------------+
- | ``n_in_sequence`` | ``int`` | number of fields visible to the |
- | | | Python side (if used as tuple) |
- +-------------------+------------------------------+------------------------------------+
+ +-------------------+------------------------------+--------------------------------------+
+ | Field | C Type | Meaning |
+ +===================+==============================+======================================+
+ | ``name`` | ``const char *`` | name of the struct sequence type |
+ +-------------------+------------------------------+--------------------------------------+
+ | ``doc`` | ``const char *`` | pointer to docstring for the type |
+ | | | or NULL to omit |
+ +-------------------+------------------------------+--------------------------------------+
+ | ``fields`` | ``PyStructSequence_Field *`` | pointer to ``NULL``-terminated array |
+ | | | with field names of the new type |
+ +-------------------+------------------------------+--------------------------------------+
+ | ``n_in_sequence`` | ``int`` | number of fields visible to the |
+ | | | Python side (if used as tuple) |
+ +-------------------+------------------------------+--------------------------------------+
.. c:type:: PyStructSequence_Field
:attr:`fields` array of the :c:type:`PyStructSequence_Desc` determines which
field of the struct sequence is described.
- +-----------+------------------+--------------------------------------+
- | Field | C Type | Meaning |
- +===========+==================+======================================+
- | ``name`` | ``const char *`` | name for the field or *NULL* to end |
- | | | the list of named fields, set to |
- | | | PyStructSequence_UnnamedField to |
- | | | leave unnamed |
- +-----------+------------------+--------------------------------------+
- | ``doc`` | ``const char *`` | field docstring or *NULL* to omit |
- +-----------+------------------+--------------------------------------+
+ +-----------+------------------+----------------------------------------+
+ | Field | C Type | Meaning |
+ +===========+==================+========================================+
+ | ``name`` | ``const char *`` | name for the field or ``NULL`` to end |
+ | | | the list of named fields, set to |
+ | | | PyStructSequence_UnnamedField to |
+ | | | leave unnamed |
+ +-----------+------------------+----------------------------------------+
+ | ``doc`` | ``const char *`` | field docstring or ``NULL`` to omit |
+ +-----------+------------------+----------------------------------------+
.. c:var:: char* PyStructSequence_UnnamedField
Generic handler for the :c:member:`~PyTypeObject.tp_alloc` slot of a type object. Use
Python's default memory allocation mechanism to allocate a new instance and
- initialize all its contents to *NULL*.
+ initialize all its contents to ``NULL``.
.. c:function:: PyObject* PyType_GenericNew(PyTypeObject *type, PyObject *args, PyObject *kwds)
.. c:function:: void* PyType_GetSlot(PyTypeObject *type, int slot)
Return the function pointer stored in the given slot. If the
- result is *NULL*, this indicates that either the slot is *NULL*,
+ result is ``NULL``, this indicates that either the slot is ``NULL``,
or that the function was called with invalid parameters.
Callers will typically cast the result pointer into the appropriate
function type.
PyObject* PyObject._ob_prev
These fields are only present when the macro ``Py_TRACE_REFS`` is defined.
- Their initialization to *NULL* is taken care of by the ``PyObject_HEAD_INIT``
- macro. For statically allocated objects, these fields always remain *NULL*.
+ Their initialization to ``NULL`` is taken care of by the ``PyObject_HEAD_INIT``
+ macro. For statically allocated objects, these fields always remain ``NULL``.
For dynamically allocated objects, these two fields are used to link the object
into a doubly-linked list of *all* live objects on the heap. This could be used
for various debugging purposes; currently the only use is to print the objects
argument to the ``PyObject_HEAD_INIT`` macro, and its value should normally be
``&PyType_Type``. However, for dynamically loadable extension modules that must
be usable on Windows (at least), the compiler complains that this is not a valid
- initializer. Therefore, the convention is to pass *NULL* to the
+ initializer. Therefore, the convention is to pass ``NULL`` to the
``PyObject_HEAD_INIT`` macro and to initialize this field explicitly at the
start of the module's initialization function, before doing anything else. This
is typically done like this::
Foo_Type.ob_type = &PyType_Type;
This should be done before any instances of the type are created.
- :c:func:`PyType_Ready` checks if :attr:`ob_type` is *NULL*, and if so,
+ :c:func:`PyType_Ready` checks if :attr:`ob_type` is ``NULL``, and if so,
initializes it to the :attr:`ob_type` field of the base class.
:c:func:`PyType_Ready` will not change this field if it is non-zero.
This field is inherited by subtypes together with :c:member:`~PyTypeObject.tp_getattro`: a subtype
inherits both :c:member:`~PyTypeObject.tp_getattr` and :c:member:`~PyTypeObject.tp_getattro` from its base type when
- the subtype's :c:member:`~PyTypeObject.tp_getattr` and :c:member:`~PyTypeObject.tp_getattro` are both *NULL*.
+ the subtype's :c:member:`~PyTypeObject.tp_getattr` and :c:member:`~PyTypeObject.tp_getattro` are both ``NULL``.
.. c:member:: setattrfunc PyTypeObject.tp_setattr
PyObject * tp_setattr(PyObject *o, char *attr_name, PyObject *v);
- The *v* argument is set to *NULL* to delete the attribute.
+ The *v* argument is set to ``NULL`` to delete the attribute.
This field is inherited by subtypes together with :c:member:`~PyTypeObject.tp_setattro`: a subtype
inherits both :c:member:`~PyTypeObject.tp_setattr` and :c:member:`~PyTypeObject.tp_setattro` from its base type when
- the subtype's :c:member:`~PyTypeObject.tp_setattr` and :c:member:`~PyTypeObject.tp_setattro` are both *NULL*.
+ the subtype's :c:member:`~PyTypeObject.tp_setattr` and :c:member:`~PyTypeObject.tp_setattro` are both ``NULL``.
.. c:member:: PyAsyncMethods* tp_as_async
This field is inherited by subtypes together with
:c:member:`~PyTypeObject.tp_richcompare`: a subtype inherits both of
:c:member:`~PyTypeObject.tp_richcompare` and :c:member:`~PyTypeObject.tp_hash`, when the subtype's
- :c:member:`~PyTypeObject.tp_richcompare` and :c:member:`~PyTypeObject.tp_hash` are both *NULL*.
+ :c:member:`~PyTypeObject.tp_richcompare` and :c:member:`~PyTypeObject.tp_hash` are both ``NULL``.
.. c:member:: ternaryfunc PyTypeObject.tp_call
An optional pointer to a function that implements calling the object. This
- should be *NULL* if the object is not callable. The signature is the same as
+ should be ``NULL`` if the object is not callable. The signature is the same as
for :c:func:`PyObject_Call`.
This field is inherited by subtypes.
This field is inherited by subtypes together with :c:member:`~PyTypeObject.tp_getattr`: a subtype
inherits both :c:member:`~PyTypeObject.tp_getattr` and :c:member:`~PyTypeObject.tp_getattro` from its base type when
- the subtype's :c:member:`~PyTypeObject.tp_getattr` and :c:member:`~PyTypeObject.tp_getattro` are both *NULL*.
+ the subtype's :c:member:`~PyTypeObject.tp_getattr` and :c:member:`~PyTypeObject.tp_getattro` are both ``NULL``.
.. c:member:: setattrofunc PyTypeObject.tp_setattro
An optional pointer to the function for setting and deleting attributes.
The signature is the same as for :c:func:`PyObject_SetAttr`, but setting
- *v* to *NULL* to delete an attribute must be supported. It is usually
+ *v* to ``NULL`` to delete an attribute must be supported. It is usually
convenient to set this field to :c:func:`PyObject_GenericSetAttr`, which
implements the normal way of setting object attributes.
This field is inherited by subtypes together with :c:member:`~PyTypeObject.tp_setattr`: a subtype
inherits both :c:member:`~PyTypeObject.tp_setattr` and :c:member:`~PyTypeObject.tp_setattro` from its base type when
- the subtype's :c:member:`~PyTypeObject.tp_setattr` and :c:member:`~PyTypeObject.tp_setattro` are both *NULL*.
+ the subtype's :c:member:`~PyTypeObject.tp_setattr` and :c:member:`~PyTypeObject.tp_setattro` are both ``NULL``.
.. c:member:: PyBufferProcs* PyTypeObject.tp_as_buffer
:c:member:`~PyTypeObject.tp_as_number`, :c:member:`~PyTypeObject.tp_as_sequence`, :c:member:`~PyTypeObject.tp_as_mapping`, and
:c:member:`~PyTypeObject.tp_as_buffer`) that were historically not always present are valid; if
such a flag bit is clear, the type fields it guards must not be accessed and
- must be considered to have a zero or *NULL* value instead.
+ must be considered to have a zero or ``NULL`` value instead.
Inheritance of this field is complicated. Most flag bits are inherited
individually, i.e. if the base type has a flag bit set, the subtype inherits
the :c:member:`~PyTypeObject.tp_traverse` and :c:member:`~PyTypeObject.tp_clear` fields, i.e. if the
:const:`Py_TPFLAGS_HAVE_GC` flag bit is clear in the subtype and the
:c:member:`~PyTypeObject.tp_traverse` and :c:member:`~PyTypeObject.tp_clear` fields in the subtype exist and have
- *NULL* values.
+ ``NULL`` values.
The following bit masks are currently defined; these can be ORed together using
the ``|`` operator to form the value of the :c:member:`~PyTypeObject.tp_flags` field. The macro
Note that :c:func:`Py_VISIT` is called only on those members that can participate
in reference cycles. Although there is also a ``self->key`` member, it can only
- be *NULL* or a Python string and therefore cannot be part of a reference cycle.
+ be ``NULL`` or a Python string and therefore cannot be part of a reference cycle.
On the other hand, even if you know a member can never be part of a cycle, as a
debugging aid you may want to visit it anyway just so the :mod:`gc` module's
Implementations of :c:member:`~PyTypeObject.tp_clear` should drop the instance's references to
those of its members that may be Python objects, and set its pointers to those
- members to *NULL*, as in the following example::
+ members to ``NULL``, as in the following example::
static int
local_clear(localobject *self)
The :c:func:`Py_CLEAR` macro should be used, because clearing references is
delicate: the reference to the contained object must not be decremented until
- after the pointer to the contained object is set to *NULL*. This is because
+ after the pointer to the contained object is set to ``NULL``. This is because
decrementing the reference count may cause the contained object to become trash,
triggering a chain of reclamation activity that may include invoking arbitrary
Python code (due to finalizers, or weakref callbacks, associated with the
contained object). If it's possible for such code to reference *self* again,
- it's important that the pointer to the contained object be *NULL* at that time,
+ it's important that the pointer to the contained object be ``NULL`` at that time,
so that *self* knows the contained object can no longer be used. The
:c:func:`Py_CLEAR` macro performs the operations in a safe order.
This field is inherited by subtypes together with :c:member:`~PyTypeObject.tp_hash`:
a subtype inherits :c:member:`~PyTypeObject.tp_richcompare` and :c:member:`~PyTypeObject.tp_hash` when
the subtype's :c:member:`~PyTypeObject.tp_richcompare` and :c:member:`~PyTypeObject.tp_hash` are both
- *NULL*.
+ ``NULL``.
The following constants are defined to be used as the third argument for
:c:member:`~PyTypeObject.tp_richcompare` and for :c:func:`PyObject_RichCompare`:
reference list head (ignoring the GC header, if present); this offset is used by
:c:func:`PyObject_ClearWeakRefs` and the :c:func:`PyWeakref_\*` functions. The
instance structure needs to include a field of type :c:type:`PyObject\*` which is
- initialized to *NULL*.
+ initialized to ``NULL``.
Do not confuse this field with :c:member:`~PyTypeObject.tp_weaklist`; that is the list head for
weak references to the type object itself.
.. c:member:: iternextfunc PyTypeObject.tp_iternext
An optional pointer to a function that returns the next item in an iterator.
- When the iterator is exhausted, it must return *NULL*; a :exc:`StopIteration`
+ When the iterator is exhausted, it must return ``NULL``; a :exc:`StopIteration`
exception may or may not be set. When another error occurs, it must return
- *NULL* too. Its presence signals that the instances of this type are
+ ``NULL`` too. Its presence signals that the instances of this type are
iterators.
Iterator types should also define the :c:member:`~PyTypeObject.tp_iter` function, and that
.. c:member:: struct PyMethodDef* PyTypeObject.tp_methods
- An optional pointer to a static *NULL*-terminated array of :c:type:`PyMethodDef`
+ An optional pointer to a static ``NULL``-terminated array of :c:type:`PyMethodDef`
structures, declaring regular methods of this type.
For each entry in the array, an entry is added to the type's dictionary (see
.. c:member:: struct PyMemberDef* PyTypeObject.tp_members
- An optional pointer to a static *NULL*-terminated array of :c:type:`PyMemberDef`
+ An optional pointer to a static ``NULL``-terminated array of :c:type:`PyMemberDef`
structures, declaring regular data members (fields or slots) of instances of
this type.
.. c:member:: struct PyGetSetDef* PyTypeObject.tp_getset
- An optional pointer to a static *NULL*-terminated array of :c:type:`PyGetSetDef`
+ An optional pointer to a static ``NULL``-terminated array of :c:type:`PyGetSetDef`
structures, declaring computed attributes of instances of this type.
For each entry in the array, an entry is added to the type's dictionary (see
The type's dictionary is stored here by :c:func:`PyType_Ready`.
- This field should normally be initialized to *NULL* before PyType_Ready is
+ This field should normally be initialized to ``NULL`` before PyType_Ready is
called; it may also be initialized to a dictionary containing initial attributes
for the type. Once :c:func:`PyType_Ready` has initialized the type, extra
attributes for the type may be added to this dictionary only if they don't
int tp_descr_set(PyObject *self, PyObject *obj, PyObject *value);
- The *value* argument is set to *NULL* to delete the value.
+ The *value* argument is set to ``NULL`` to delete the value.
This field is inherited by subtypes.
.. XXX explain.
arguments represent positional and keyword arguments of the call to
:meth:`__init__`.
- The :c:member:`~PyTypeObject.tp_init` function, if not *NULL*, is called when an instance is
+ The :c:member:`~PyTypeObject.tp_init` function, if not ``NULL``, is called when an instance is
created normally by calling its type, after the type's :c:member:`~PyTypeObject.tp_new` function
has returned an instance of the type. If the :c:member:`~PyTypeObject.tp_new` function returns an
instance of some other type that is not a subtype of the original type, no
An optional pointer to an instance creation function.
- If this function is *NULL* for a particular type, that type cannot be called to
+ If this function is ``NULL`` for a particular type, that type cannot be called to
create new instances; presumably there is some other way to create instances,
like a factory function.
deferred to :c:member:`~PyTypeObject.tp_init`.
This field is inherited by subtypes, except it is not inherited by static types
- whose :c:member:`~PyTypeObject.tp_base` is *NULL* or ``&PyBaseObject_Type``.
+ whose :c:member:`~PyTypeObject.tp_base` is ``NULL`` or ``&PyBaseObject_Type``.
.. c:member:: destructor PyTypeObject.tp_free
Tuple of base types.
- This is set for types created by a class statement. It should be *NULL* for
+ This is set for types created by a class statement. It should be ``NULL`` for
statically defined types.
This field is not inherited.
This function is used by :c:func:`PyMapping_Size` and
:c:func:`PyObject_Size`, and has the same signature. This slot may be set to
- *NULL* if the object has no defined length.
+ ``NULL`` if the object has no defined length.
.. c:member:: binaryfunc PyMappingMethods.mp_subscript
This function is used by :c:func:`PyObject_GetItem` and
:c:func:`PySequence_GetSlice`, and has the same signature as
:c:func:`!PyObject_GetItem`. This slot must be filled for the
- :c:func:`PyMapping_Check` function to return ``1``, it can be *NULL*
+ :c:func:`PyMapping_Check` function to return ``1``, it can be ``NULL``
otherwise.
.. c:member:: objobjargproc PyMappingMethods.mp_ass_subscript
This function is used by :c:func:`PyObject_SetItem`,
:c:func:`PyObject_DelItem`, :c:func:`PyObject_SetSlice` and
:c:func:`PyObject_DelSlice`. It has the same signature as
- :c:func:`!PyObject_SetItem`, but *v* can also be set to *NULL* to delete
- an item. If this slot is *NULL*, the object does not support item
+ :c:func:`!PyObject_SetItem`, but *v* can also be set to ``NULL`` to delete
+ an item. If this slot is ``NULL``, the object does not support item
assignment and deletion.
signature. It is also used by :c:func:`PyObject_GetItem`, after trying
the subscription via the :c:member:`~PyMappingMethods.mp_subscript` slot.
This slot must be filled for the :c:func:`PySequence_Check`
- function to return ``1``, it can be *NULL* otherwise.
+ function to return ``1``, it can be ``NULL`` otherwise.
Negative indexes are handled as follows: if the :attr:`sq_length` slot is
filled, it is called and the sequence length is used to compute a positive
- index which is passed to :attr:`sq_item`. If :attr:`sq_length` is *NULL*,
+ index which is passed to :attr:`sq_item`. If :attr:`sq_length` is ``NULL``,
the index is passed as is to the function.
.. c:member:: ssizeobjargproc PySequenceMethods.sq_ass_item
signature. It is also used by :c:func:`PyObject_SetItem` and
:c:func:`PyObject_DelItem`, after trying the item assignment and deletion
via the :c:member:`~PyMappingMethods.mp_ass_subscript` slot.
- This slot may be left to *NULL* if the object does not support
+ This slot may be left to ``NULL`` if the object does not support
item assignment and deletion.
.. c:member:: objobjproc PySequenceMethods.sq_contains
This function may be used by :c:func:`PySequence_Contains` and has the same
- signature. This slot may be left to *NULL*, in this case
+ signature. This slot may be left to ``NULL``, in this case
:c:func:`!PySequence_Contains` simply traverses the sequence until it
finds a match.
This function is used by :c:func:`PySequence_InPlaceConcat` and has the same
signature. It should modify its first operand, and return it. This slot
- may be left to *NULL*, in this case :c:func:`!PySequence_InPlaceConcat`
+ may be left to ``NULL``, in this case :c:func:`!PySequence_InPlaceConcat`
will fall back to :c:func:`PySequence_Concat`. It is also used by the
augmented assignment ``+=``, after trying numeric in-place addition
via the :c:member:`~PyNumberMethods.nb_inplace_add` slot.
This function is used by :c:func:`PySequence_InPlaceRepeat` and has the same
signature. It should modify its first operand, and return it. This slot
- may be left to *NULL*, in this case :c:func:`!PySequence_InPlaceRepeat`
+ may be left to ``NULL``, in this case :c:func:`!PySequence_InPlaceRepeat`
will fall back to :c:func:`PySequence_Repeat`. It is also used by the
augmented assignment ``*=``, after trying numeric in-place multiplication
via the :c:member:`~PyNumberMethods.nb_inplace_multiply` slot.
steps:
(1) Check if the request can be met. If not, raise :c:data:`PyExc_BufferError`,
- set :c:data:`view->obj` to *NULL* and return ``-1``.
+ set :c:data:`view->obj` to ``NULL`` and return ``-1``.
(2) Fill in the requested fields.
Handle a request to release the resources of the buffer. If no resources
need to be released, :c:member:`PyBufferProcs.bf_releasebuffer` may be
- *NULL*. Otherwise, a standard implementation of this function will take
+ ``NULL``. Otherwise, a standard implementation of this function will take
these optional steps:
(1) Decrement an internal counter for the number of exports.
The returned object must be an iterator, i.e. :c:func:`PyIter_Check` must
return ``1`` for it.
- This slot may be set to *NULL* if an object is not an :term:`awaitable`.
+ This slot may be set to ``NULL`` if an object is not an :term:`awaitable`.
.. c:member:: unaryfunc PyAsyncMethods.am_aiter
Must return an :term:`awaitable` object. See :meth:`__anext__` for details.
- This slot may be set to *NULL* if an object does not implement
+ This slot may be set to ``NULL`` if an object does not implement
asynchronous iteration protocol.
.. c:member:: unaryfunc PyAsyncMethods.am_anext
PyObject *am_anext(PyObject *self)
Must return an :term:`awaitable` object. See :meth:`__anext__` for details.
- This slot may be set to *NULL*.
+ This slot may be set to ``NULL``.
.. versionchanged:: 3.3
This macro is now inefficient -- because in many cases the
:c:type:`Py_UNICODE` representation does not exist and needs to be created
- -- and can fail (return *NULL* with an exception set). Try to port the
+ -- and can fail (return ``NULL`` with an exception set). Try to port the
code to use the new :c:func:`PyUnicode_nBYTE_DATA` macros or use
:c:func:`PyUnicode_WRITE` or :c:func:`PyUnicode_READ`.
Create a Unicode object from the char buffer *u*. The bytes will be
interpreted as being UTF-8 encoded. The buffer is copied into the new
- object. If the buffer is not *NULL*, the return value might be a shared
+ object. If the buffer is not ``NULL``, the return value might be a shared
object, i.e. modification of the data is not allowed.
- If *u* is *NULL*, this function behaves like :c:func:`PyUnicode_FromUnicode`
- with the buffer set to *NULL*. This usage is deprecated in favor of
+ If *u* is ``NULL``, this function behaves like :c:func:`PyUnicode_FromUnicode`
+ with the buffer set to ``NULL``. This usage is deprecated in favor of
:c:func:`PyUnicode_New`.
.. tabularcolumns:: |l|l|L|
- +-------------------+---------------------+--------------------------------+
- | Format Characters | Type | Comment |
- +===================+=====================+================================+
- | :attr:`%%` | *n/a* | The literal % character. |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%c` | int | A single character, |
- | | | represented as a C int. |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%d` | int | Equivalent to |
- | | | ``printf("%d")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%u` | unsigned int | Equivalent to |
- | | | ``printf("%u")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%ld` | long | Equivalent to |
- | | | ``printf("%ld")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%li` | long | Equivalent to |
- | | | ``printf("%li")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%lu` | unsigned long | Equivalent to |
- | | | ``printf("%lu")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%lld` | long long | Equivalent to |
- | | | ``printf("%lld")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%lli` | long long | Equivalent to |
- | | | ``printf("%lli")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%llu` | unsigned long long | Equivalent to |
- | | | ``printf("%llu")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%zd` | Py_ssize_t | Equivalent to |
- | | | ``printf("%zd")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%zi` | Py_ssize_t | Equivalent to |
- | | | ``printf("%zi")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%zu` | size_t | Equivalent to |
- | | | ``printf("%zu")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%i` | int | Equivalent to |
- | | | ``printf("%i")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%x` | int | Equivalent to |
- | | | ``printf("%x")``. [1]_ |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%s` | const char\* | A null-terminated C character |
- | | | array. |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%p` | const void\* | The hex representation of a C |
- | | | pointer. Mostly equivalent to |
- | | | ``printf("%p")`` except that |
- | | | it is guaranteed to start with |
- | | | the literal ``0x`` regardless |
- | | | of what the platform's |
- | | | ``printf`` yields. |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%A` | PyObject\* | The result of calling |
- | | | :func:`ascii`. |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%U` | PyObject\* | A Unicode object. |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%V` | PyObject\*, | A Unicode object (which may be |
- | | const char\* | *NULL*) and a null-terminated |
- | | | C character array as a second |
- | | | parameter (which will be used, |
- | | | if the first parameter is |
- | | | *NULL*). |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%S` | PyObject\* | The result of calling |
- | | | :c:func:`PyObject_Str`. |
- +-------------------+---------------------+--------------------------------+
- | :attr:`%R` | PyObject\* | The result of calling |
- | | | :c:func:`PyObject_Repr`. |
- +-------------------+---------------------+--------------------------------+
+ +-------------------+---------------------+----------------------------------+
+ | Format Characters | Type | Comment |
+ +===================+=====================+==================================+
+ | :attr:`%%` | *n/a* | The literal % character. |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%c` | int | A single character, |
+ | | | represented as a C int. |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%d` | int | Equivalent to |
+ | | | ``printf("%d")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%u` | unsigned int | Equivalent to |
+ | | | ``printf("%u")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%ld` | long | Equivalent to |
+ | | | ``printf("%ld")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%li` | long | Equivalent to |
+ | | | ``printf("%li")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%lu` | unsigned long | Equivalent to |
+ | | | ``printf("%lu")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%lld` | long long | Equivalent to |
+ | | | ``printf("%lld")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%lli` | long long | Equivalent to |
+ | | | ``printf("%lli")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%llu` | unsigned long long | Equivalent to |
+ | | | ``printf("%llu")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%zd` | Py_ssize_t | Equivalent to |
+ | | | ``printf("%zd")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%zi` | Py_ssize_t | Equivalent to |
+ | | | ``printf("%zi")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%zu` | size_t | Equivalent to |
+ | | | ``printf("%zu")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%i` | int | Equivalent to |
+ | | | ``printf("%i")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%x` | int | Equivalent to |
+ | | | ``printf("%x")``. [1]_ |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%s` | const char\* | A null-terminated C character |
+ | | | array. |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%p` | const void\* | The hex representation of a C |
+ | | | pointer. Mostly equivalent to |
+ | | | ``printf("%p")`` except that |
+ | | | it is guaranteed to start with |
+ | | | the literal ``0x`` regardless |
+ | | | of what the platform's |
+ | | | ``printf`` yields. |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%A` | PyObject\* | The result of calling |
+ | | | :func:`ascii`. |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%U` | PyObject\* | A Unicode object. |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%V` | PyObject\*, | A Unicode object (which may be |
+ | | const char\* | ``NULL``) and a null-terminated |
+ | | | C character array as a second |
+ | | | parameter (which will be used, |
+ | | | if the first parameter is |
+ | | | ``NULL``). |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%S` | PyObject\* | The result of calling |
+ | | | :c:func:`PyObject_Str`. |
+ +-------------------+---------------------+----------------------------------+
+ | :attr:`%R` | PyObject\* | The result of calling |
+ | | | :c:func:`PyObject_Repr`. |
+ +-------------------+---------------------+----------------------------------+
An unrecognized format character causes all the rest of the format string to be
copied as-is to the result string, and any extra arguments discarded.
:class:`bytes`, :class:`bytearray` and other
:term:`bytes-like objects <bytes-like object>`
are decoded according to the given *encoding* and using the error handling
- defined by *errors*. Both can be *NULL* to have the interface use the default
+ defined by *errors*. Both can be ``NULL`` to have the interface use the default
values (see :ref:`builtincodecs` for details).
All other objects, including Unicode objects, cause a :exc:`TypeError` to be
set.
- The API returns *NULL* if there was an error. The caller is responsible for
+ The API returns ``NULL`` if there was an error. The caller is responsible for
decref'ing the returned objects.
Py_ssize_t buflen, int copy_null)
Copy the string *u* into a UCS4 buffer, including a null character, if
- *copy_null* is set. Returns *NULL* and sets an exception on error (in
+ *copy_null* is set. Returns ``NULL`` and sets an exception on error (in
particular, a :exc:`SystemError` if *buflen* is smaller than the length of
*u*). *buffer* is returned on success.
.. c:function:: Py_UCS4* PyUnicode_AsUCS4Copy(PyObject *u)
Copy the string *u* into a new UCS4 buffer that is allocated using
- :c:func:`PyMem_Malloc`. If this fails, *NULL* is returned with a
+ :c:func:`PyMem_Malloc`. If this fails, ``NULL`` is returned with a
:exc:`MemoryError` set. The returned buffer always has an extra
null code point appended.
.. c:function:: PyObject* PyUnicode_FromUnicode(const Py_UNICODE *u, Py_ssize_t size)
Create a Unicode object from the Py_UNICODE buffer *u* of the given size. *u*
- may be *NULL* which causes the contents to be undefined. It is the user's
+ may be ``NULL`` which causes the contents to be undefined. It is the user's
responsibility to fill in the needed data. The buffer is copied into the new
object.
- If the buffer is not *NULL*, the return value might be a shared object.
+ If the buffer is not ``NULL``, the return value might be a shared object.
Therefore, modification of the resulting Unicode object is only allowed when
- *u* is *NULL*.
+ *u* is ``NULL``.
- If the buffer is *NULL*, :c:func:`PyUnicode_READY` must be called once the
+ If the buffer is ``NULL``, :c:func:`PyUnicode_READY` must be called once the
string content has been filled before using any of the access macros such as
:c:func:`PyUnicode_KIND`.
.. c:function:: Py_UNICODE* PyUnicode_AsUnicode(PyObject *unicode)
Return a read-only pointer to the Unicode object's internal
- :c:type:`Py_UNICODE` buffer, or *NULL* on error. This will create the
+ :c:type:`Py_UNICODE` buffer, or ``NULL`` on error. This will create the
:c:type:`Py_UNICODE*` representation of the object if it is not yet
available. The buffer is always terminated with an extra null code point.
Note that the resulting :c:type:`Py_UNICODE` string may also contain
Create a Unicode object by replacing all decimal digits in
:c:type:`Py_UNICODE` buffer of the given *size* by ASCII digits 0--9
- according to their decimal value. Return *NULL* if an exception occurs.
+ according to their decimal value. Return ``NULL`` if an exception occurs.
.. c:function:: Py_UNICODE* PyUnicode_AsUnicodeAndSize(PyObject *unicode, Py_ssize_t *size)
.. c:function:: Py_UNICODE* PyUnicode_AsUnicodeCopy(PyObject *unicode)
- Create a copy of a Unicode string ending with a null code point. Return *NULL*
+ Create a copy of a Unicode string ending with a null code point. Return ``NULL``
and raise a :exc:`MemoryError` exception on memory allocation failure,
otherwise return a new allocated buffer (use :c:func:`PyMem_Free` to free
the buffer). Note that the resulting :c:type:`Py_UNICODE*` string may
Create a Unicode object from the :c:type:`wchar_t` buffer *w* of the given *size*.
Passing ``-1`` as the *size* indicates that the function must itself compute the length,
using wcslen.
- Return *NULL* on failure.
+ Return ``NULL`` on failure.
.. c:function:: Py_ssize_t PyUnicode_AsWideChar(PyObject *unicode, wchar_t *w, Py_ssize_t size)
.. c:function:: wchar_t* PyUnicode_AsWideCharString(PyObject *unicode, Py_ssize_t *size)
Convert the Unicode object to a wide character string. The output string
- always ends with a null character. If *size* is not *NULL*, write the number
+ always ends with a null character. If *size* is not ``NULL``, write the number
of wide characters (excluding the trailing null termination character) into
*\*size*. Note that the resulting :c:type:`wchar_t` string might contain
null characters, which would cause the string to be truncated when used with
- most C functions. If *size* is *NULL* and the :c:type:`wchar_t*` string
+ most C functions. If *size* is ``NULL`` and the :c:type:`wchar_t*` string
contains null characters a :exc:`ValueError` is raised.
Returns a buffer allocated by :c:func:`PyMem_Alloc` (use
- :c:func:`PyMem_Free` to free it) on success. On error, returns *NULL*
+ :c:func:`PyMem_Free` to free it) on success. On error, returns ``NULL``
and *\*size* is undefined. Raises a :exc:`MemoryError` if memory allocation
is failed.
.. versionadded:: 3.2
.. versionchanged:: 3.7
- Raises a :exc:`ValueError` if *size* is *NULL* and the :c:type:`wchar_t*`
+ Raises a :exc:`ValueError` if *size* is ``NULL`` and the :c:type:`wchar_t*`
string contains null characters.
have the same semantics as the ones of the built-in :func:`str` string object
constructor.
-Setting encoding to *NULL* causes the default encoding to be used
+Setting encoding to ``NULL`` causes the default encoding to be used
which is ASCII. The file system calls should use
:c:func:`PyUnicode_FSConverter` for encoding file names. This uses the
variable :c:data:`Py_FileSystemDefaultEncoding` internally. This
pointer to a static string, on others, it will change at run-time
(such as when the application invokes setlocale).
-Error handling is set by errors which may also be set to *NULL* meaning to use
+Error handling is set by errors which may also be set to ``NULL`` meaning to use
the default handling defined for the codec. Default error handling for all
built-in codecs is "strict" (:exc:`ValueError` is raised).
Create a Unicode object by decoding *size* bytes of the encoded string *s*.
*encoding* and *errors* have the same meaning as the parameters of the same name
in the :func:`str` built-in function. The codec to be used is looked up
- using the Python codec registry. Return *NULL* if an exception was raised by
+ using the Python codec registry. Return ``NULL`` if an exception was raised by
the codec.
Encode a Unicode object and return the result as Python bytes object.
*encoding* and *errors* have the same meaning as the parameters of the same
name in the Unicode :meth:`~str.encode` method. The codec to be used is looked up
- using the Python codec registry. Return *NULL* if an exception was raised by
+ using the Python codec registry. Return ``NULL`` if an exception was raised by
the codec.
Encode the :c:type:`Py_UNICODE` buffer *s* of the given *size* and return a Python
bytes object. *encoding* and *errors* have the same meaning as the
parameters of the same name in the Unicode :meth:`~str.encode` method. The codec
- to be used is looked up using the Python codec registry. Return *NULL* if an
+ to be used is looked up using the Python codec registry. Return ``NULL`` if an
exception was raised by the codec.
.. deprecated-removed:: 3.3 4.0
.. c:function:: PyObject* PyUnicode_DecodeUTF8(const char *s, Py_ssize_t size, const char *errors)
Create a Unicode object by decoding *size* bytes of the UTF-8 encoded string
- *s*. Return *NULL* if an exception was raised by the codec.
+ *s*. Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_DecodeUTF8Stateful(const char *s, Py_ssize_t size, \
const char *errors, Py_ssize_t *consumed)
- If *consumed* is *NULL*, behave like :c:func:`PyUnicode_DecodeUTF8`. If
- *consumed* is not *NULL*, trailing incomplete UTF-8 byte sequences will not be
+ If *consumed* is ``NULL``, behave like :c:func:`PyUnicode_DecodeUTF8`. If
+ *consumed* is not ``NULL``, trailing incomplete UTF-8 byte sequences will not be
treated as an error. Those bytes will not be decoded and the number of bytes
that have been decoded will be stored in *consumed*.
.. c:function:: PyObject* PyUnicode_AsUTF8String(PyObject *unicode)
Encode a Unicode object using UTF-8 and return the result as Python bytes
- object. Error handling is "strict". Return *NULL* if an exception was
+ object. Error handling is "strict". Return ``NULL`` if an exception was
raised by the codec.
Return a pointer to the UTF-8 encoding of the Unicode object, and
store the size of the encoded representation (in bytes) in *size*. The
- *size* argument can be *NULL*; in this case no size will be stored. The
+ *size* argument can be ``NULL``; in this case no size will be stored. The
returned buffer always has an extra null byte appended (not included in
*size*), regardless of whether there are any other null code points.
- In the case of an error, *NULL* is returned with an exception set and no
+ In the case of an error, ``NULL`` is returned with an exception set and no
*size* is stored.
This caches the UTF-8 representation of the string in the Unicode object, and
.. c:function:: PyObject* PyUnicode_EncodeUTF8(const Py_UNICODE *s, Py_ssize_t size, const char *errors)
Encode the :c:type:`Py_UNICODE` buffer *s* of the given *size* using UTF-8 and
- return a Python bytes object. Return *NULL* if an exception was raised by
+ return a Python bytes object. Return ``NULL`` if an exception was raised by
the codec.
.. deprecated-removed:: 3.3 4.0
const char *errors, int *byteorder)
Decode *size* bytes from a UTF-32 encoded buffer string and return the
- corresponding Unicode object. *errors* (if non-*NULL*) defines the error
+ corresponding Unicode object. *errors* (if non-``NULL``) defines the error
handling. It defaults to "strict".
- If *byteorder* is non-*NULL*, the decoder starts decoding using the given byte
+ If *byteorder* is non-``NULL``, the decoder starts decoding using the given byte
order::
*byteorder == -1: little endian
After completion, *\*byteorder* is set to the current byte order at the end
of input data.
- If *byteorder* is *NULL*, the codec starts in native order mode.
+ If *byteorder* is ``NULL``, the codec starts in native order mode.
- Return *NULL* if an exception was raised by the codec.
+ Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_DecodeUTF32Stateful(const char *s, Py_ssize_t size, \
const char *errors, int *byteorder, Py_ssize_t *consumed)
- If *consumed* is *NULL*, behave like :c:func:`PyUnicode_DecodeUTF32`. If
- *consumed* is not *NULL*, :c:func:`PyUnicode_DecodeUTF32Stateful` will not treat
+ If *consumed* is ``NULL``, behave like :c:func:`PyUnicode_DecodeUTF32`. If
+ *consumed* is not ``NULL``, :c:func:`PyUnicode_DecodeUTF32Stateful` will not treat
trailing incomplete UTF-32 byte sequences (such as a number of bytes not divisible
by four) as an error. Those bytes will not be decoded and the number of bytes
that have been decoded will be stored in *consumed*.
Return a Python byte string using the UTF-32 encoding in native byte
order. The string always starts with a BOM mark. Error handling is "strict".
- Return *NULL* if an exception was raised by the codec.
+ Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_EncodeUTF32(const Py_UNICODE *s, Py_ssize_t size, \
If *Py_UNICODE_WIDE* is not defined, surrogate pairs will be output
as a single code point.
- Return *NULL* if an exception was raised by the codec.
+ Return ``NULL`` if an exception was raised by the codec.
.. deprecated-removed:: 3.3 4.0
Part of the old-style :c:type:`Py_UNICODE` API; please migrate to using
const char *errors, int *byteorder)
Decode *size* bytes from a UTF-16 encoded buffer string and return the
- corresponding Unicode object. *errors* (if non-*NULL*) defines the error
+ corresponding Unicode object. *errors* (if non-``NULL``) defines the error
handling. It defaults to "strict".
- If *byteorder* is non-*NULL*, the decoder starts decoding using the given byte
+ If *byteorder* is non-``NULL``, the decoder starts decoding using the given byte
order::
*byteorder == -1: little endian
After completion, *\*byteorder* is set to the current byte order at the end
of input data.
- If *byteorder* is *NULL*, the codec starts in native order mode.
+ If *byteorder* is ``NULL``, the codec starts in native order mode.
- Return *NULL* if an exception was raised by the codec.
+ Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_DecodeUTF16Stateful(const char *s, Py_ssize_t size, \
const char *errors, int *byteorder, Py_ssize_t *consumed)
- If *consumed* is *NULL*, behave like :c:func:`PyUnicode_DecodeUTF16`. If
- *consumed* is not *NULL*, :c:func:`PyUnicode_DecodeUTF16Stateful` will not treat
+ If *consumed* is ``NULL``, behave like :c:func:`PyUnicode_DecodeUTF16`. If
+ *consumed* is not ``NULL``, :c:func:`PyUnicode_DecodeUTF16Stateful` will not treat
trailing incomplete UTF-16 byte sequences (such as an odd number of bytes or a
split surrogate pair) as an error. Those bytes will not be decoded and the
number of bytes that have been decoded will be stored in *consumed*.
Return a Python byte string using the UTF-16 encoding in native byte
order. The string always starts with a BOM mark. Error handling is "strict".
- Return *NULL* if an exception was raised by the codec.
+ Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_EncodeUTF16(const Py_UNICODE *s, Py_ssize_t size, \
represented as a surrogate pair. If it is not defined, each :c:type:`Py_UNICODE`
values is interpreted as a UCS-2 character.
- Return *NULL* if an exception was raised by the codec.
+ Return ``NULL`` if an exception was raised by the codec.
.. deprecated-removed:: 3.3 4.0
Part of the old-style :c:type:`Py_UNICODE` API; please migrate to using
.. c:function:: PyObject* PyUnicode_DecodeUTF7(const char *s, Py_ssize_t size, const char *errors)
Create a Unicode object by decoding *size* bytes of the UTF-7 encoded string
- *s*. Return *NULL* if an exception was raised by the codec.
+ *s*. Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_DecodeUTF7Stateful(const char *s, Py_ssize_t size, \
const char *errors, Py_ssize_t *consumed)
- If *consumed* is *NULL*, behave like :c:func:`PyUnicode_DecodeUTF7`. If
- *consumed* is not *NULL*, trailing incomplete UTF-7 base-64 sections will not
+ If *consumed* is ``NULL``, behave like :c:func:`PyUnicode_DecodeUTF7`. If
+ *consumed* is not ``NULL``, trailing incomplete UTF-7 base-64 sections will not
be treated as an error. Those bytes will not be decoded and the number of
bytes that have been decoded will be stored in *consumed*.
int base64SetO, int base64WhiteSpace, const char *errors)
Encode the :c:type:`Py_UNICODE` buffer of the given size using UTF-7 and
- return a Python bytes object. Return *NULL* if an exception was raised by
+ return a Python bytes object. Return ``NULL`` if an exception was raised by
the codec.
If *base64SetO* is nonzero, "Set O" (punctuation that has no otherwise
Py_ssize_t size, const char *errors)
Create a Unicode object by decoding *size* bytes of the Unicode-Escape encoded
- string *s*. Return *NULL* if an exception was raised by the codec.
+ string *s*. Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_AsUnicodeEscapeString(PyObject *unicode)
Encode a Unicode object using Unicode-Escape and return the result as a
- bytes object. Error handling is "strict". Return *NULL* if an exception was
+ bytes object. Error handling is "strict". Return ``NULL`` if an exception was
raised by the codec.
.. c:function:: PyObject* PyUnicode_EncodeUnicodeEscape(const Py_UNICODE *s, Py_ssize_t size)
Encode the :c:type:`Py_UNICODE` buffer of the given *size* using Unicode-Escape and
- return a bytes object. Return *NULL* if an exception was raised by the codec.
+ return a bytes object. Return ``NULL`` if an exception was raised by the codec.
.. deprecated-removed:: 3.3 4.0
Part of the old-style :c:type:`Py_UNICODE` API; please migrate to using
Py_ssize_t size, const char *errors)
Create a Unicode object by decoding *size* bytes of the Raw-Unicode-Escape
- encoded string *s*. Return *NULL* if an exception was raised by the codec.
+ encoded string *s*. Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_AsRawUnicodeEscapeString(PyObject *unicode)
Encode a Unicode object using Raw-Unicode-Escape and return the result as
- a bytes object. Error handling is "strict". Return *NULL* if an exception
+ a bytes object. Error handling is "strict". Return ``NULL`` if an exception
was raised by the codec.
Py_ssize_t size)
Encode the :c:type:`Py_UNICODE` buffer of the given *size* using Raw-Unicode-Escape
- and return a bytes object. Return *NULL* if an exception was raised by the codec.
+ and return a bytes object. Return ``NULL`` if an exception was raised by the codec.
.. deprecated-removed:: 3.3 4.0
Part of the old-style :c:type:`Py_UNICODE` API; please migrate to using
.. c:function:: PyObject* PyUnicode_DecodeLatin1(const char *s, Py_ssize_t size, const char *errors)
Create a Unicode object by decoding *size* bytes of the Latin-1 encoded string
- *s*. Return *NULL* if an exception was raised by the codec.
+ *s*. Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_AsLatin1String(PyObject *unicode)
Encode a Unicode object using Latin-1 and return the result as Python bytes
- object. Error handling is "strict". Return *NULL* if an exception was
+ object. Error handling is "strict". Return ``NULL`` if an exception was
raised by the codec.
.. c:function:: PyObject* PyUnicode_EncodeLatin1(const Py_UNICODE *s, Py_ssize_t size, const char *errors)
Encode the :c:type:`Py_UNICODE` buffer of the given *size* using Latin-1 and
- return a Python bytes object. Return *NULL* if an exception was raised by
+ return a Python bytes object. Return ``NULL`` if an exception was raised by
the codec.
.. deprecated-removed:: 3.3 4.0
.. c:function:: PyObject* PyUnicode_DecodeASCII(const char *s, Py_ssize_t size, const char *errors)
Create a Unicode object by decoding *size* bytes of the ASCII encoded string
- *s*. Return *NULL* if an exception was raised by the codec.
+ *s*. Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_AsASCIIString(PyObject *unicode)
Encode a Unicode object using ASCII and return the result as Python bytes
- object. Error handling is "strict". Return *NULL* if an exception was
+ object. Error handling is "strict". Return ``NULL`` if an exception was
raised by the codec.
.. c:function:: PyObject* PyUnicode_EncodeASCII(const Py_UNICODE *s, Py_ssize_t size, const char *errors)
Encode the :c:type:`Py_UNICODE` buffer of the given *size* using ASCII and
- return a Python bytes object. Return *NULL* if an exception was raised by
+ return a Python bytes object. Return ``NULL`` if an exception was raised by
the codec.
.. deprecated-removed:: 3.3 4.0
PyObject *mapping, const char *errors)
Create a Unicode object by decoding *size* bytes of the encoded string *s*
- using the given *mapping* object. Return *NULL* if an exception was raised
+ using the given *mapping* object. Return ``NULL`` if an exception was raised
by the codec.
- If *mapping* is *NULL*, Latin-1 decoding will be applied. Else
+ If *mapping* is ``NULL``, Latin-1 decoding will be applied. Else
*mapping* must map bytes ordinals (integers in the range from 0 to 255)
to Unicode strings, integers (which are then interpreted as Unicode
ordinals) or ``None``. Unmapped data bytes -- ones which cause a
.. c:function:: PyObject* PyUnicode_AsCharmapString(PyObject *unicode, PyObject *mapping)
Encode a Unicode object using the given *mapping* object and return the
- result as a bytes object. Error handling is "strict". Return *NULL* if an
+ result as a bytes object. Error handling is "strict". Return ``NULL`` if an
exception was raised by the codec.
The *mapping* object must map Unicode ordinal integers to bytes objects,
PyObject *mapping, const char *errors)
Encode the :c:type:`Py_UNICODE` buffer of the given *size* using the given
- *mapping* object and return the result as a bytes object. Return *NULL* if
+ *mapping* object and return the result as a bytes object. Return ``NULL`` if
an exception was raised by the codec.
.. deprecated-removed:: 3.3 4.0
PyObject *mapping, const char *errors)
Translate a Unicode object using the given *mapping* object and return the
- resulting Unicode object. Return *NULL* if an exception was raised by the
+ resulting Unicode object. Return ``NULL`` if an exception was raised by the
codec.
The *mapping* object must map Unicode ordinal integers to Unicode strings,
Translate a :c:type:`Py_UNICODE` buffer of the given *size* by applying a
character *mapping* table to it and return the resulting Unicode object.
- Return *NULL* when an exception was raised by the codec.
+ Return ``NULL`` when an exception was raised by the codec.
.. deprecated-removed:: 3.3 4.0
Part of the old-style :c:type:`Py_UNICODE` API; please migrate to using
.. c:function:: PyObject* PyUnicode_DecodeMBCS(const char *s, Py_ssize_t size, const char *errors)
Create a Unicode object by decoding *size* bytes of the MBCS encoded string *s*.
- Return *NULL* if an exception was raised by the codec.
+ Return ``NULL`` if an exception was raised by the codec.
.. c:function:: PyObject* PyUnicode_DecodeMBCSStateful(const char *s, Py_ssize_t size, \
const char *errors, Py_ssize_t *consumed)
- If *consumed* is *NULL*, behave like :c:func:`PyUnicode_DecodeMBCS`. If
- *consumed* is not *NULL*, :c:func:`PyUnicode_DecodeMBCSStateful` will not decode
+ If *consumed* is ``NULL``, behave like :c:func:`PyUnicode_DecodeMBCS`. If
+ *consumed* is not ``NULL``, :c:func:`PyUnicode_DecodeMBCSStateful` will not decode
trailing lead byte and the number of bytes that have been decoded will be stored
in *consumed*.
.. c:function:: PyObject* PyUnicode_AsMBCSString(PyObject *unicode)
Encode a Unicode object using MBCS and return the result as Python bytes
- object. Error handling is "strict". Return *NULL* if an exception was
+ object. Error handling is "strict". Return ``NULL`` if an exception was
raised by the codec.
.. c:function:: PyObject* PyUnicode_EncodeCodePage(int code_page, PyObject *unicode, const char *errors)
Encode the Unicode object using the specified code page and return a Python
- bytes object. Return *NULL* if an exception was raised by the codec. Use
+ bytes object. Return ``NULL`` if an exception was raised by the codec. Use
:c:data:`CP_ACP` code page to get the MBCS encoder.
.. versionadded:: 3.3
.. c:function:: PyObject* PyUnicode_EncodeMBCS(const Py_UNICODE *s, Py_ssize_t size, const char *errors)
Encode the :c:type:`Py_UNICODE` buffer of the given *size* using MBCS and return
- a Python bytes object. Return *NULL* if an exception was raised by the
+ a Python bytes object. Return ``NULL`` if an exception was raised by the
codec.
.. deprecated-removed:: 3.3 4.0
(we refer to them as strings in the descriptions) and return Unicode objects or
integers as appropriate.
-They all return *NULL* or ``-1`` if an exception occurs.
+They all return ``NULL`` or ``-1`` if an exception occurs.
.. c:function:: PyObject* PyUnicode_Concat(PyObject *left, PyObject *right)
.. c:function:: PyObject* PyUnicode_Split(PyObject *s, PyObject *sep, Py_ssize_t maxsplit)
- Split a string giving a list of Unicode strings. If *sep* is *NULL*, splitting
+ Split a string giving a list of Unicode strings. If *sep* is ``NULL``, splitting
will be done at all whitespace substrings. Otherwise, splits occur at the given
separator. At most *maxsplit* splits will be done. If negative, no limit is
set. Separators are not included in the resulting list.
and sequences work well. Unmapped character ordinals (ones which cause a
:exc:`LookupError`) are left untouched and are copied as-is.
- *errors* has the usual meaning for codecs. It may be *NULL* which indicates to
+ *errors* has the usual meaning for codecs. It may be ``NULL`` which indicates to
use the default error handling.
.. c:function:: int PyRun_AnyFile(FILE *fp, const char *filename)
This is a simplified interface to :c:func:`PyRun_AnyFileExFlags` below, leaving
- *closeit* set to ``0`` and *flags* set to *NULL*.
+ *closeit* set to ``0`` and *flags* set to ``NULL``.
.. c:function:: int PyRun_AnyFileFlags(FILE *fp, const char *filename, PyCompilerFlags *flags)
.. c:function:: int PyRun_AnyFileEx(FILE *fp, const char *filename, int closeit)
This is a simplified interface to :c:func:`PyRun_AnyFileExFlags` below, leaving
- the *flags* argument set to *NULL*.
+ the *flags* argument set to ``NULL``.
.. c:function:: int PyRun_AnyFileExFlags(FILE *fp, const char *filename, int closeit, PyCompilerFlags *flags)
terminal input or Unix pseudo-terminal), return the value of
:c:func:`PyRun_InteractiveLoop`, otherwise return the result of
:c:func:`PyRun_SimpleFile`. *filename* is decoded from the filesystem
- encoding (:func:`sys.getfilesystemencoding`). If *filename* is *NULL*, this
+ encoding (:func:`sys.getfilesystemencoding`). If *filename* is ``NULL``, this
function uses ``"???"`` as the filename.
.. c:function:: int PyRun_SimpleFile(FILE *fp, const char *filename)
This is a simplified interface to :c:func:`PyRun_SimpleFileExFlags` below,
- leaving *closeit* set to ``0`` and *flags* set to *NULL*.
+ leaving *closeit* set to ``0`` and *flags* set to ``NULL``.
.. c:function:: int PyRun_SimpleFileEx(FILE *fp, const char *filename, int closeit)
This is a simplified interface to :c:func:`PyRun_SimpleFileExFlags` below,
- leaving *flags* set to *NULL*.
+ leaving *flags* set to ``NULL``.
.. c:function:: int PyRun_SimpleFileExFlags(FILE *fp, const char *filename, int closeit, PyCompilerFlags *flags)
.. c:function:: int PyRun_InteractiveOne(FILE *fp, const char *filename)
This is a simplified interface to :c:func:`PyRun_InteractiveOneFlags` below,
- leaving *flags* set to *NULL*.
+ leaving *flags* set to ``NULL``.
.. c:function:: int PyRun_InteractiveOneFlags(FILE *fp, const char *filename, PyCompilerFlags *flags)
.. c:function:: int PyRun_InteractiveLoop(FILE *fp, const char *filename)
This is a simplified interface to :c:func:`PyRun_InteractiveLoopFlags` below,
- leaving *flags* set to *NULL*.
+ leaving *flags* set to ``NULL``.
.. c:function:: int PyRun_InteractiveLoopFlags(FILE *fp, const char *filename, PyCompilerFlags *flags)
``char *func(FILE *stdin, FILE *stdout, char *prompt)``,
overriding the default function used to read a single line of input
at the interpreter's prompt. The function is expected to output
- the string *prompt* if it's not *NULL*, and then read a line of
+ the string *prompt* if it's not ``NULL``, and then read a line of
input from the provided standard input file, returning the
resulting string. For example, The :mod:`readline` module sets
this hook to provide line-editing and tab-completion features.
The result must be a string allocated by :c:func:`PyMem_RawMalloc` or
- :c:func:`PyMem_RawRealloc`, or *NULL* if an error occurred.
+ :c:func:`PyMem_RawRealloc`, or ``NULL`` if an error occurred.
.. versionchanged:: 3.4
The result must be allocated by :c:func:`PyMem_RawMalloc` or
This is a simplified interface to
:c:func:`PyParser_SimpleParseStringFlagsFilename` below, leaving *filename* set
- to *NULL* and *flags* set to ``0``.
+ to ``NULL`` and *flags* set to ``0``.
.. c:function:: struct _node* PyParser_SimpleParseStringFlags( const char *str, int start, int flags)
This is a simplified interface to
:c:func:`PyParser_SimpleParseStringFlagsFilename` below, leaving *filename* set
- to *NULL*.
+ to ``NULL``.
.. c:function:: struct _node* PyParser_SimpleParseStringFlagsFilename( const char *str, const char *filename, int start, int flags)
.. c:function:: PyObject* PyRun_String(const char *str, int start, PyObject *globals, PyObject *locals)
This is a simplified interface to :c:func:`PyRun_StringFlags` below, leaving
- *flags* set to *NULL*.
+ *flags* set to ``NULL``.
.. c:function:: PyObject* PyRun_StringFlags(const char *str, int start, PyObject *globals, PyObject *locals, PyCompilerFlags *flags)
that implements the mapping protocol. The parameter *start* specifies
the start token that should be used to parse the source code.
- Returns the result of executing the code as a Python object, or *NULL* if an
+ Returns the result of executing the code as a Python object, or ``NULL`` if an
exception was raised.
.. c:function:: PyObject* PyRun_File(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals)
This is a simplified interface to :c:func:`PyRun_FileExFlags` below, leaving
- *closeit* set to ``0`` and *flags* set to *NULL*.
+ *closeit* set to ``0`` and *flags* set to ``NULL``.
.. c:function:: PyObject* PyRun_FileEx(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals, int closeit)
This is a simplified interface to :c:func:`PyRun_FileExFlags` below, leaving
- *flags* set to *NULL*.
+ *flags* set to ``NULL``.
.. c:function:: PyObject* PyRun_FileFlags(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals, PyCompilerFlags *flags)
.. c:function:: PyObject* Py_CompileString(const char *str, const char *filename, int start)
This is a simplified interface to :c:func:`Py_CompileStringFlags` below, leaving
- *flags* set to *NULL*.
+ *flags* set to ``NULL``.
.. c:function:: PyObject* Py_CompileStringFlags(const char *str, const char *filename, int start, PyCompilerFlags *flags)
code which can be compiled and should be :const:`Py_eval_input`,
:const:`Py_file_input`, or :const:`Py_single_input`. The filename specified by
*filename* is used to construct the code object and may appear in tracebacks or
- :exc:`SyntaxError` exception messages. This returns *NULL* if the code
+ :exc:`SyntaxError` exception messages. This returns ``NULL`` if the code
cannot be parsed or compiled.
The integer *optimize* specifies the optimization level of the compiler; a
This is a simplified interface to :c:func:`PyEval_EvalCodeEx`, with just
the code object, and global and local variables. The other arguments are
- set to *NULL*.
+ set to ``NULL``.
.. c:function:: PyObject* PyEval_EvalCodeEx(PyObject *co, PyObject *globals, PyObject *locals, PyObject *const *args, int argcount, PyObject *const *kws, int kwcount, PyObject *const *defs, int defcount, PyObject *kwdefs, PyObject *closure)
executed, it is passed as ``PyCompilerFlags *flags``. In this case, ``from
__future__ import`` can modify *flags*.
- Whenever ``PyCompilerFlags *flags`` is *NULL*, :attr:`cf_flags` is treated as
+ Whenever ``PyCompilerFlags *flags`` is ``NULL``, :attr:`cf_flags` is treated as
equal to ``0``, and any modification due to ``from __future__ import`` is
discarded. ::
reference object may be returned. The second parameter, *callback*, can be a
callable object that receives notification when *ob* is garbage collected; it
should accept a single parameter, which will be the weak reference object
- itself. *callback* may also be ``None`` or *NULL*. If *ob* is not a
+ itself. *callback* may also be ``None`` or ``NULL``. If *ob* is not a
weakly-referencable object, or if *callback* is not callable, ``None``, or
- *NULL*, this will return *NULL* and raise :exc:`TypeError`.
+ ``NULL``, this will return ``NULL`` and raise :exc:`TypeError`.
.. c:function:: PyObject* PyWeakref_NewProxy(PyObject *ob, PyObject *callback)
existing proxy object may be returned. The second parameter, *callback*, can
be a callable object that receives notification when *ob* is garbage
collected; it should accept a single parameter, which will be the weak
- reference object itself. *callback* may also be ``None`` or *NULL*. If *ob*
+ reference object itself. *callback* may also be ``None`` or ``NULL``. If *ob*
is not a weakly-referencable object, or if *callback* is not callable,
- ``None``, or *NULL*, this will return *NULL* and raise :exc:`TypeError`.
+ ``None``, or ``NULL``, this will return ``NULL`` and raise :exc:`TypeError`.
.. c:function:: PyObject* PyWeakref_GetObject(PyObject *ref)
pValue = PyObject_CallObject(pFunc, pArgs);
-Upon return of the function, ``pValue`` is either *NULL* or it contains a
+Upon return of the function, ``pValue`` is either ``NULL`` or it contains a
reference to the return value of the function. Be sure to release the reference
after examining the value.
type and its components have been stored in the variables whose addresses are
passed. It returns false (zero) if an invalid argument list was passed. In the
latter case it also raises an appropriate exception so the calling function can
-return *NULL* immediately (as we saw in the example).
+return ``NULL`` immediately (as we saw in the example).
.. _extending-errors:
An important convention throughout the Python interpreter is the following: when
a function fails, it should set an exception condition and return an error value
-(usually a *NULL* pointer). Exceptions are stored in a static global variable
-inside the interpreter; if this variable is *NULL* no exception has occurred. A
+(usually a ``NULL`` pointer). Exceptions are stored in a static global variable
+inside the interpreter; if this variable is ``NULL`` no exception has occurred. A
second global variable stores the "associated value" of the exception (the
second argument to :keyword:`raise`). A third variable contains the stack
traceback in case the error originated in Python code. These three variables
to any of these functions.
You can test non-destructively whether an exception has been set with
-:c:func:`PyErr_Occurred`. This returns the current exception object, or *NULL*
+:c:func:`PyErr_Occurred`. This returns the current exception object, or ``NULL``
if no exception has occurred. You normally don't need to call
:c:func:`PyErr_Occurred` to see whether an error occurred in a function call,
since you should be able to tell from the return value.
When a function *f* that calls another function *g* detects that the latter
-fails, *f* should itself return an error value (usually *NULL* or ``-1``). It
+fails, *f* should itself return an error value (usually ``NULL`` or ``-1``). It
should *not* call one of the :c:func:`PyErr_\*` functions --- one has already
been called by *g*. *f*'s caller is then supposed to also return an error
indication to *its* caller, again *without* calling :c:func:`PyErr_\*`, and so on
Note that the Python name for the exception object is :exc:`spam.error`. The
:c:func:`PyErr_NewException` function may create a class with the base class
-being :exc:`Exception` (unless another class is passed in instead of *NULL*),
+being :exc:`Exception` (unless another class is passed in instead of ``NULL``),
described in :ref:`bltin-exceptions`.
Note also that the :c:data:`SpamError` variable retains a reference to the newly
if (!PyArg_ParseTuple(args, "s", &command))
return NULL;
-It returns *NULL* (the error indicator for functions returning object pointers)
+It returns ``NULL`` (the error indicator for functions returning object pointers)
if an error is detected in the argument list, relying on the exception set by
:c:func:`PyArg_ParseTuple`. Otherwise the string value of the argument has been
copied to the local variable :c:data:`command`. This is a pointer assignment and
return Py_None;
:c:data:`Py_None` is the C name for the special Python object ``None``. It is a
-genuine Python object rather than a *NULL* pointer, which means "error" in most
+genuine Python object rather than a ``NULL`` pointer, which means "error" in most
contexts, as we have seen.
table (an array of :c:type:`PyMethodDef` structures) found in the module definition.
:c:func:`PyModule_Create` returns a pointer to the module object
that it creates. It may abort with a fatal error for
-certain errors, or return *NULL* if the module could not be initialized
+certain errors, or return ``NULL`` if the module could not be initialized
satisfactorily. The init function must return the module object to its caller,
so that it then gets inserted into ``sys.modules``.
:ref:`parsetuple`.
The macros :c:func:`Py_XINCREF` and :c:func:`Py_XDECREF` increment/decrement the
-reference count of an object and are safe in the presence of *NULL* pointers
-(but note that *temp* will not be *NULL* in this context). More info on them
+reference count of an object and are safe in the presence of ``NULL`` pointers
+(but note that *temp* will not be ``NULL`` in this context). More info on them
in section :ref:`refcounts`.
.. index:: single: PyObject_CallObject()
interested in its value.
Before you do this, however, it is important to check that the return value
-isn't *NULL*. If it is, the Python function terminated by raising an exception.
+isn't ``NULL``. If it is, the Python function terminated by raising an exception.
If the C code that called :c:func:`PyObject_CallObject` is called from Python, it
should now return an error indication to its Python caller, so the interpreter
can print a stack trace, or the calling Python code can handle the exception.
The *arg* and *format* parameters are identical to those of the
:c:func:`PyArg_ParseTuple` function. The *kwdict* parameter is the dictionary of
keywords received as the third parameter from the Python runtime. The *kwlist*
-parameter is a *NULL*-terminated list of strings which identify the parameters;
+parameter is a ``NULL``-terminated list of strings which identify the parameters;
the names are matched with the type information from *format* from left to
right. On success, :c:func:`PyArg_ParseTupleAndKeywords` returns true, otherwise
it returns false and raises an appropriate exception.
-------------
In general, functions that take object references as arguments do not expect you
-to pass them *NULL* pointers, and will dump core (or cause later core dumps) if
-you do so. Functions that return object references generally return *NULL* only
-to indicate that an exception occurred. The reason for not testing for *NULL*
+to pass them ``NULL`` pointers, and will dump core (or cause later core dumps) if
+you do so. Functions that return object references generally return ``NULL`` only
+to indicate that an exception occurred. The reason for not testing for ``NULL``
arguments is that functions often pass the objects they receive on to other
-function --- if each function were to test for *NULL*, there would be a lot of
+function --- if each function were to test for ``NULL``, there would be a lot of
redundant tests and the code would run more slowly.
-It is better to test for *NULL* only at the "source:" when a pointer that may be
-*NULL* is received, for example, from :c:func:`malloc` or from a function that
+It is better to test for ``NULL`` only at the "source:" when a pointer that may be
+``NULL`` is received, for example, from :c:func:`malloc` or from a function that
may raise an exception.
-The macros :c:func:`Py_INCREF` and :c:func:`Py_DECREF` do not check for *NULL*
+The macros :c:func:`Py_INCREF` and :c:func:`Py_DECREF` do not check for ``NULL``
pointers --- however, their variants :c:func:`Py_XINCREF` and :c:func:`Py_XDECREF`
do.
The macros for checking for a particular object type (``Pytype_Check()``) don't
-check for *NULL* pointers --- again, there is much code that calls several of
+check for ``NULL`` pointers --- again, there is much code that calls several of
these in a row to test an object against various different expected types, and
-this would generate redundant tests. There are no variants with *NULL*
+this would generate redundant tests. There are no variants with ``NULL``
checking.
The C function calling mechanism guarantees that the argument list passed to C
-functions (``args`` in the examples) is never *NULL* --- in fact it guarantees
+functions (``args`` in the examples) is never ``NULL`` --- in fact it guarantees
that it is always a tuple [#]_.
-It is a severe error to ever let a *NULL* pointer "escape" to the Python user.
+It is a severe error to ever let a ``NULL`` pointer "escape" to the Python user.
.. Frank Stajano:
A pedagogically buggy example, along the lines of the previous listing, would
Whichever method you choose, it's important to name your Capsules properly.
The function :c:func:`PyCapsule_New` takes a name parameter
-(:c:type:`const char \*`); you're permitted to pass in a *NULL* name, but
+(:c:type:`const char \*`); you're permitted to pass in a ``NULL`` name, but
we strongly encourage you to specify a name. Properly named Capsules provide
a degree of runtime type-safety; there is no feasible way to tell one unnamed
Capsule from another.
provide the functions that control how the attributes are resolved. There needs
to be a function which can retrieve attributes (if any are defined), and another
to set attributes (if setting attributes is allowed). Removing an attribute is
-a special case, for which the new value passed to the handler is *NULL*.
+a special case, for which the new value passed to the handler is ``NULL``.
Python supports two pairs of attribute handlers; a type that supports attributes
only needs to implement the functions for one pair. The difference is that one
When :c:func:`PyType_Ready` is called, it uses three tables referenced by the
type object to create :term:`descriptor`\s which are placed in the dictionary of the
type object. Each descriptor controls access to one attribute of the instance
-object. Each of the tables is optional; if all three are *NULL*, instances of
+object. Each of the tables is optional; if all three are ``NULL``, instances of
the type will only have attributes that are inherited from their base type, and
-should leave the :c:member:`~PyTypeObject.tp_getattro` and :c:member:`~PyTypeObject.tp_setattro` fields *NULL* as
+should leave the :c:member:`~PyTypeObject.tp_getattro` and :c:member:`~PyTypeObject.tp_setattro` fields ``NULL`` as
well, allowing the base type to handle attributes.
The tables are declared as three fields of the type object::
struct PyMemberDef *tp_members;
struct PyGetSetDef *tp_getset;
-If :c:member:`~PyTypeObject.tp_methods` is not *NULL*, it must refer to an array of
+If :c:member:`~PyTypeObject.tp_methods` is not ``NULL``, it must refer to an array of
:c:type:`PyMethodDef` structures. Each entry in the table is an instance of this
structure::
One entry should be defined for each method provided by the type; no entries are
needed for methods inherited from a base type. One additional entry is needed
at the end; it is a sentinel that marks the end of the array. The
-:attr:`ml_name` field of the sentinel must be *NULL*.
+:attr:`ml_name` field of the sentinel must be ``NULL``.
The second table is used to define attributes which map directly to data stored
in the instance. A variety of primitive C types are supported, and access may
class object, and get the doc string using its :attr:`__doc__` attribute.
As with the :c:member:`~PyTypeObject.tp_methods` table, a sentinel entry with a :attr:`name` value
-of *NULL* is required.
+of ``NULL`` is required.
.. XXX Descriptors need to be explained in more detail somewhere, but not here.
The :c:member:`~PyTypeObject.tp_setattr` handler is called when the :meth:`__setattr__` or
:meth:`__delattr__` method of a class instance would be called. When an
-attribute should be deleted, the third parameter will be *NULL*. Here is an
+attribute should be deleted, the third parameter will be ``NULL``. Here is an
example that simply raises an exception; if this were really all you wanted, the
-:c:member:`~PyTypeObject.tp_setattr` handler should be set to *NULL*. ::
+:c:member:`~PyTypeObject.tp_setattr` handler should be set to ``NULL``. ::
static int
newdatatype_setattr(newdatatypeobject *obj, char *name, PyObject *v)
``Py_LT`` or ``Py_GT``. It should compare the two objects with respect to the
specified operator and return ``Py_True`` or ``Py_False`` if the comparison is
successful, ``Py_NotImplemented`` to indicate that comparison is not
-implemented and the other object's comparison method should be tried, or *NULL*
+implemented and the other object's comparison method should be tried, or ``NULL``
if an exception was set.
Here is a sample implementation, for a datatype that is considered equal if the
blocks of handlers referenced by the type object. For newer protocols there are
additional slots in the main type object, with a flag bit being set to indicate
that the slots are present and should be checked by the interpreter. (The flag
-bit does not indicate that the slot values are non-*NULL*. The flag may be set
+bit does not indicate that the slot values are non-``NULL``. The flag may be set
to indicate the presence of a slot, but a slot may still be unfilled.) ::
PyNumberMethods *tp_as_number;
:c:func:`PyArg_ParseTuple` to extract the arguments.
#. *kwds* is a dictionary of keyword arguments that were passed. If this is
- non-*NULL* and you support keyword arguments, use
+ non-``NULL`` and you support keyword arguments, use
:c:func:`PyArg_ParseTupleAndKeywords` to extract the arguments. If you
- do not want to support keyword arguments and this is non-*NULL*, raise a
+ do not want to support keyword arguments and this is non-``NULL``, raise a
:exc:`TypeError` with a message saying that keyword arguments are not supported.
Here is a toy ``tp_call`` implementation::
These functions provide support for the iterator protocol. Both handlers
take exactly one parameter, the instance for which they are being called,
and return a new reference. In the case of an error, they should set an
-exception and return *NULL*. :c:member:`~PyTypeObject.tp_iter` corresponds
+exception and return ``NULL``. :c:member:`~PyTypeObject.tp_iter` corresponds
to the Python :meth:`__iter__` method, while :c:member:`~PyTypeObject.tp_iternext`
corresponds to the Python :meth:`~iterator.__next__` method.
to the iterator. Its :c:member:`~PyTypeObject.tp_iternext` handler should
return a new reference to the next object in the iteration, if there is one.
If the iteration has reached the end, :c:member:`~PyTypeObject.tp_iternext`
-may return *NULL* without setting an exception, or it may set
-:exc:`StopIteration` *in addition* to returning *NULL*; avoiding
+may return ``NULL`` without setting an exception, or it may set
+:exc:`StopIteration` *in addition* to returning ``NULL``; avoiding
the exception can yield slightly better performance. If an actual error
occurs, :c:member:`~PyTypeObject.tp_iternext` should always set an exception
-and return *NULL*.
+and return ``NULL``.
.. _weakref-support:
#. Include a :c:type:`PyObject\*` field in the C object structure dedicated to
the weak reference mechanism. The object's constructor should leave it
- *NULL* (which is automatic when using the default
+ ``NULL`` (which is automatic when using the default
:c:member:`~PyTypeObject.tp_alloc`).
#. Set the :c:member:`~PyTypeObject.tp_weaklistoffset` type member
The only further addition is that ``tp_dealloc`` needs to clear any weak
references (by calling :c:func:`PyObject_ClearWeakRefs`) if the field is
-non-*NULL*::
+non-``NULL``::
static void
Trivial_dealloc(TrivialObject *self)
This initializes the :class:`Custom` type, filling in a number of members
to the appropriate default values, including :attr:`ob_type` that we initially
-set to *NULL*. ::
+set to ``NULL``. ::
Py_INCREF(&CustomType);
if (PyModule_AddObject(m, "Custom", (PyObject *) &CustomType) < 0) {
This method first clears the reference counts of the two Python attributes.
:c:func:`Py_XDECREF` correctly handles the case where its argument is
-*NULL* (which might happen here if ``tp_new`` failed midway). It then
+``NULL`` (which might happen here if ``tp_new`` failed midway). It then
calls the :c:member:`~PyTypeObject.tp_free` member of the object's type
(computed by ``Py_TYPE(self)``) to free the object's memory. Note that
the object's type might not be :class:`CustomType`, because the object may
It is not required to define a ``tp_new`` member, and indeed many extension
types will simply reuse :c:func:`PyType_GenericNew` as done in the first
version of the ``Custom`` type above. In this case, we use the ``tp_new``
-handler to initialize the ``first`` and ``last`` attributes to non-*NULL*
+handler to initialize the ``first`` and ``last`` attributes to non-``NULL``
default values.
``tp_new`` is passed the type being instantiated (not necessarily ``CustomType``,
self = (CustomObject *) type->tp_alloc(type, 0);
Since memory allocation may fail, we must check the :c:member:`~PyTypeObject.tp_alloc`
-result against *NULL* before proceeding.
+result against ``NULL`` before proceeding.
.. note::
We didn't fill the :c:member:`~PyTypeObject.tp_alloc` slot ourselves. Rather
A disadvantage of this approach is that it doesn't provide a way to restrict the
types of objects that can be assigned to the Python attributes. We expect the
first and last names to be strings, but any Python objects can be assigned.
-Further, the attributes can be deleted, setting the C pointers to *NULL*. Even
-though we can make sure the members are initialized to non-*NULL* values, the
-members can be set to *NULL* if the attributes are deleted.
+Further, the attributes can be deleted, setting the C pointers to ``NULL``. Even
+though we can make sure the members are initialized to non-``NULL`` values, the
+members can be set to ``NULL`` if the attributes are deleted.
We define a single method, :meth:`Custom.name()`, that outputs the objects name as the
concatenation of the first and last names. ::
return "%s %s" % (self.first, self.last)
Note that we have to check for the possibility that our :attr:`first` and
-:attr:`last` members are *NULL*. This is because they can be deleted, in which
-case they are set to *NULL*. It would be better to prevent deletion of these
+:attr:`last` members are ``NULL``. This is because they can be deleted, in which
+case they are set to ``NULL``. It would be better to prevent deletion of these
attributes and to restrict the attribute values to be strings. We'll see how to
do that in the next section.
that decide the attribute to get or set based on data in the closure.)
The setter function is passed the :class:`Custom` object, the new value, and the
-closure. The new value may be *NULL*, in which case the attribute is being
+closure. The new value may be ``NULL``, in which case the attribute is being
deleted. In our setter, we raise an error if the attribute is deleted or if its
new value is not a string.
.tp_getset = Custom_getsetters,
The last item in a :c:type:`PyGetSetDef` structure is the "closure" mentioned
-above. In this case, we aren't using a closure, so we just pass *NULL*.
+above. In this case, we aren't using a closure, so we just pass ``NULL``.
We also remove the member definitions for these attributes::
}
With these changes, we can assure that the ``first`` and ``last`` members are
-never *NULL* so we can remove checks for *NULL* values in almost all cases.
+never ``NULL`` so we can remove checks for ``NULL`` values in almost all cases.
This means that most of the :c:func:`Py_XDECREF` calls can be converted to
:c:func:`Py_DECREF` calls. The only place we can't change these calls is in
the ``tp_dealloc`` implementation, where there is the possibility that the
Notice the use of the :c:func:`Py_CLEAR` macro. It is the recommended and safe
way to clear data attributes of arbitrary types while decrementing
their reference counts. If you were to call :c:func:`Py_XDECREF` instead
-on the attribute before setting it to *NULL*, there is a possibility
+on the attribute before setting it to ``NULL``, there is a possibility
that the attribute's destructor would call back into code that reads the
attribute again (*especially* if there is a reference cycle).
length. Note that Python bytes objects may contain null bytes so C's
:c:func:`strlen` should not be used.
-To test the type of an object, first make sure it isn't *NULL*, and then use
+To test the type of an object, first make sure it isn't ``NULL``, and then use
:c:func:`PyBytes_Check`, :c:func:`PyTuple_Check`, :c:func:`PyList_Check`, etc.
There is also a high-level API to Python objects which is provided by the
Quoting the docs for that value:
This pointer is initialized to point to an array of :c:type:`struct _frozen`
- records, terminated by one whose members are all *NULL* or zero. When a frozen
+ records, terminated by one whose members are all ``NULL`` or zero. When a frozen
module is imported, it is searched in this table. Third-party code could play
tricks with this to provide a dynamically created collection of frozen modules.
* The result of the :c:data:`PyOS_ReadlineFunctionPointer` callback must
now be a string allocated by :c:func:`PyMem_RawMalloc` or
- :c:func:`PyMem_RawRealloc`, or *NULL* if an error occurred, instead of a
+ :c:func:`PyMem_RawRealloc`, or ``NULL`` if an error occurred, instead of a
string allocated by :c:func:`PyMem_Malloc` or :c:func:`PyMem_Realloc`
(:issue:`16742`)
(Contributed by Serhiy Storchaka in :issue:`6532`.)
:c:func:`PyUnicode_AsWideCharString` now raises a :exc:`ValueError` if the
-second argument is *NULL* and the :c:type:`wchar_t*` string contains null
+second argument is ``NULL`` and the :c:type:`wchar_t*` string contains null
characters. (Contributed by Serhiy Storchaka in :issue:`30708`.)
Changes to the startup sequence and the management of dynamic memory
/* Call a callable Python object 'callable' with arguments given by the
tuple 'args' and keywords arguments given by the dictionary 'kwargs'.
- 'args' must not be *NULL*, use an empty tuple if no arguments are
+ 'args' must not be NULL, use an empty tuple if no arguments are
needed. If no named arguments are needed, 'kwargs' can be NULL.
This is the equivalent of the Python expression:
/* Call a callable Python object 'callable', with arguments given by the
- tuple 'args'. If no arguments are needed, then 'args' can be *NULL*.
+ tuple 'args'. If no arguments are needed, then 'args' can be NULL.
- Returns the result of the call on success, or *NULL* on failure.
+ Returns the result of the call on success, or NULL on failure.
This is the equivalent of the Python expression:
callable(*args). */
projects / thirdparty / Python / cpython.git / commitdiff
