-/* GNU Objective C Runtime internal declarations
- Copyright (C) 1993, 1995, 1996, 1997, 2002 Free Software Foundation, Inc.
- Contributed by Kresten Krab Thorup
+/* GNU Objective-C Runtime API - Modern API
+ Copyright (C) 2010-2013 Free Software Foundation, Inc.
+ Contributed by Nicola Pero <nicola.pero@meta-innovation.com>
-This file is part of GNU CC.
+This file is part of GCC.
-GNU CC is free software; you can redistribute it and/or modify it under the
-terms of the GNU General Public License as published by the Free Software
-Foundation; either version 2, or (at your option) any later version.
+GCC is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 3, or (at your option) any
+later version.
-GNU CC is distributed in the hope that it will be useful, but WITHOUT ANY
-WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
-FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
-details.
+GCC is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
+License for more details.
-You should have received a copy of the GNU General Public License along with
-GNU CC; see the file COPYING. If not, write to the Free Software
-Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
-/* As a special exception, if you link this library with files compiled with
- GCC to produce an executable, this does not cause the resulting executable
- to be covered by the GNU General Public License. This exception does not
- however invalidate any other reasons why the executable file might be
- covered by the GNU General Public License. */
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+<http://www.gnu.org/licenses/>. */
#ifndef __objc_runtime_INCLUDE_GNU
#define __objc_runtime_INCLUDE_GNU
-#include <stdarg.h> /* for varargs and va_list's */
+/*
+ This file declares the "modern" GNU Objective-C Runtime API.
-#include <stdio.h>
-#include <ctype.h>
+ This API replaced the "traditional" GNU Objective-C Runtime API
+ (which used to be declared in objc/objc-api.h) which is the one
+ supported by older versions of the GNU Objective-C Runtime. The
+ "modern" API is very similar to the API used by the modern
+ Apple/NeXT runtime.
+*/
+#include "objc.h"
+#include "objc-decls.h"
-#include <stddef.h> /* so noone else will get system versions */
-#include "assert.h"
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
-#include "objc/objc.h" /* core data types */
-#include "objc/objc-api.h" /* runtime api functions */
+/* An 'Ivar' represents an instance variable. It holds information
+ about the name, type and offset of the instance variable. */
+typedef struct objc_ivar *Ivar;
-#include "objc/thr.h" /* thread and mutex support */
+/* A 'Property' represents a property. It holds information about the
+ name of the property, and its attributes.
-#include "objc/hash.h" /* hash structures */
-#include "objc/objc-list.h" /* linear lists */
+ Compatibility Note: the Apple/NeXT runtime defines this as
+ objc_property_t, so we define it that way as well, but obviously
+ Property is the right name. */
+typedef struct objc_property *Property;
+typedef struct objc_property *objc_property_t;
-extern void __objc_add_class_to_hash(Class); /* (objc-class.c) */
-extern void __objc_init_selector_tables(void); /* (objc-sel.c) */
-extern void __objc_init_class_tables(void); /* (objc-class.c) */
-extern void __objc_init_dispatch_tables(void); /* (objc-dispatch.c) */
-extern void __objc_install_premature_dtable(Class); /* (objc-dispatch.c) */
-extern void __objc_resolve_class_links(void); /* (objc-class.c) */
-extern void __objc_register_selectors_from_class(Class); /* (objc-sel.c) */
-extern void __objc_update_dispatch_table_for_class (Class);/* (objc-msg.c) */
+/* A 'Method' represents a method. It holds information about the
+ name, types and the IMP of the method. */
+typedef struct objc_method *Method;
-extern int __objc_init_thread_system(void); /* thread.c */
-extern int __objc_fini_thread_system(void); /* thread.c */
-extern void __objc_print_dtable_stats(void); /* sendmsg.c */
+/* A 'Category' represents a category. It holds information about the
+ name of the category, the class it belongs to, and the methods,
+ protocols and such like provided by the category. */
+typedef struct objc_category *Category;
-extern void class_add_method_list(Class, MethodList_t);
+/* 'Protocol' is defined in objc/objc.h (which is included by this
+ file). */
-/* Registering instance methods as class methods for root classes */
-extern void __objc_register_instance_methods_to_class(Class);
-extern Method_t search_for_method_in_list(MethodList_t list, SEL op);
+/* Method descriptor returned by introspective Object methods. At the
+ moment, this is really just the first part of the more complete
+ objc_method structure used internally by the runtime. (PS: In the
+ GNU Objective-C Runtime, selectors already include a type, so an
+ objc_method_description does not add much to a SEL. But in other
+ runtimes, that is not the case, which is why
+ objc_method_description exists). */
+struct objc_method_description
+{
+ SEL name; /* Selector (name and signature) */
+ char *types; /* Type encoding */
+};
-/* True when class links has been resolved */
-extern BOOL __objc_class_links_resolved;
+/* The following are used in encode strings to describe the type of
+ Ivars and Methods. */
+#define _C_ID '@'
+#define _C_CLASS '#'
+#define _C_SEL ':'
+#define _C_CHR 'c'
+#define _C_UCHR 'C'
+#define _C_SHT 's'
+#define _C_USHT 'S'
+#define _C_INT 'i'
+#define _C_UINT 'I'
+#define _C_LNG 'l'
+#define _C_ULNG 'L'
+#define _C_LNG_LNG 'q'
+#define _C_ULNG_LNG 'Q'
+#define _C_FLT 'f'
+#define _C_DBL 'd'
+#define _C_LNG_DBL 'D'
+#define _C_BFLD 'b'
+#define _C_BOOL 'B'
+#define _C_VOID 'v'
+#define _C_UNDEF '?'
+#define _C_PTR '^'
+#define _C_CHARPTR '*'
+#define _C_ARY_B '['
+#define _C_ARY_E ']'
+#define _C_UNION_B '('
+#define _C_UNION_E ')'
+#define _C_STRUCT_B '{'
+#define _C_STRUCT_E '}'
+#define _C_VECTOR '!'
+#define _C_COMPLEX 'j'
-/* Number of selectors stored in each of the selector tables */
-extern unsigned int __objc_selector_max_index;
+/* _C_ATOM is never generated by the compiler. You can treat it as
+ equivalent to "*". */
+#define _C_ATOM '%'
-/* Mutex locking __objc_selector_max_index and its arrays. */
-extern objc_mutex_t __objc_runtime_mutex;
+/* The following are used in encode strings to describe some
+ qualifiers of method and ivar types. */
+#define _C_CONST 'r'
+#define _C_IN 'n'
+#define _C_INOUT 'N'
+#define _C_OUT 'o'
+#define _C_BYCOPY 'O'
+#define _C_BYREF 'R'
+#define _C_ONEWAY 'V'
+#define _C_GCINVISIBLE '|'
-/* Number of threads which are alive. */
-extern int __objc_runtime_threads_alive;
+/* The same when used as flags. */
+#define _F_CONST 0x01
+#define _F_IN 0x01
+#define _F_OUT 0x02
+#define _F_INOUT 0x03
+#define _F_BYCOPY 0x04
+#define _F_BYREF 0x08
+#define _F_ONEWAY 0x10
+#define _F_GCINVISIBLE 0x20
-#ifdef DEBUG
-#define DEBUG_PRINTF(format, args...) printf (format, ## args)
-#else
-#define DEBUG_PRINTF(format, args...)
-#endif
-BOOL __objc_responds_to (id object, SEL sel); /* for internal use only! */
-SEL __sel_register_typed_name (const char*, const char*,
- struct objc_selector*, BOOL is_const);
-extern void __objc_generate_gc_type_description (Class);
+/** Implementation: the following functions are defined inline. */
-#endif /* not __objc_runtime_INCLUDE_GNU */
+/* Return the class of 'object', or Nil if the object is nil. If
+ 'object' is a class, the meta class is returned; if 'object' is a
+ meta class, the root meta class is returned (note that this is
+ different from the traditional GNU Objective-C Runtime API function
+ object_get_class(), which for a meta class would return the meta
+ class itself). This function is inline, so it is really fast and
+ should be used instead of accessing object->class_pointer
+ directly. */
+static inline Class
+object_getClass (id object)
+{
+ if (object != nil)
+ return object->class_pointer;
+ else
+ return Nil;
+}
+/** Implementation: the following functions are in selector.c. */
+
+/* Return the name of a given selector. If 'selector' is NULL, return
+ "<null selector>". */
+objc_EXPORT const char *sel_getName (SEL selector);
+
+/* Return the type of a given selector. Return NULL if selector is
+ NULL.
+
+ Compatibility Note: the Apple/NeXT runtime has untyped selectors,
+ so it does not have this function, which is specific to the GNU
+ Runtime. */
+objc_EXPORT const char *sel_getTypeEncoding (SEL selector);
+
+/* This is the same as sel_registerName (). Please use
+ sel_registerName () instead. */
+objc_EXPORT SEL sel_getUid (const char *name);
+
+/* Register a selector with a given name (but unspecified types). If
+ you know the types, it is better to call sel_registerTypedName().
+ If a selector with this name and no types already exists, it is
+ returned. Note that this function should really be called
+ 'objc_registerSelector'. Return NULL if 'name' is NULL. */
+objc_EXPORT SEL sel_registerName (const char *name);
+
+/* Register a selector with a given name and types. If a selector
+ with this name and types already exists, it is returned. Note that
+ this function should really be called 'objc_registerTypedSelector',
+ and it's called 'sel_registerTypedName' only for consistency with
+ 'sel_registerName'. Return NULL if 'name' is NULL.
+
+ Compatibility Note: the Apple/NeXT runtime has untyped selectors,
+ so it does not have this function, which is specific to the GNU
+ Runtime. */
+objc_EXPORT SEL sel_registerTypedName (const char *name, const char *type);
+
+/* Return YES if first_selector is the same as second_selector, and NO
+ if not. */
+objc_EXPORT BOOL sel_isEqual (SEL first_selector, SEL second_selector);
+
+/* Return all the selectors with the supplied name. In the GNU
+ runtime, selectors are typed and there may be multiple selectors
+ with the same name but a different type. The return value of the
+ function is a pointer to an area, allocated with malloc(), that
+ contains all the selectors with the supplier name known to the
+ runtime. The list is terminated by NULL. Optionally, if you pass
+ a non-NULL 'numberOfReturnedSelectors' pointer, the unsigned int
+ that it points to will be filled with the number of selectors
+ returned.
+
+ Compatibility Note: the Apple/NeXT runtime has untyped selectors,
+ so it does not have this function, which is specific to the GNU
+ Runtime. */
+objc_EXPORT SEL * sel_copyTypedSelectorList (const char *name,
+ unsigned int *numberOfReturnedSelectors);
+
+/* Return a selector with name 'name' and a non-zero type encoding, if
+ there is a single selector with a type, and with that name,
+ registered with the runtime. If there is no such selector, or if
+ there are multiple selectors with the same name but conflicting
+ types, NULL is returned. Return NULL if 'name' is NULL.
+
+ This is useful if you have the name of the selector, and would
+ really like to get a selector for it that includes the type
+ encoding. Unfortunately, if the program contains multiple selector
+ with the same name but different types, sel_getTypedSelector can
+ not possibly know which one you need, and so will return NULL.
+
+ Compatibility Note: the Apple/NeXT runtime has untyped selectors,
+ so it does not have this function, which is specific to the GNU
+ Runtime. */
+objc_EXPORT SEL sel_getTypedSelector (const char *name);
+
+
+/** Implementation: the following functions are in objects.c. */
+
+/* Create an instance of class 'class_', adding extraBytes to the size
+ of the returned object. This method allocates the appropriate
+ amount of memory for the instance, initializes it to zero, then
+ calls all the C++ constructors on appropriate C++ instance
+ variables of the instance (if any) (TODO: The C++ constructors bit
+ is not implemented yet). */
+objc_EXPORT id class_createInstance (Class class_, size_t extraBytes);
+
+/* Copy an object and return the copy. extraBytes should be identical
+ to the extraBytes parameter that was passed when creating the
+ original object. */
+objc_EXPORT id object_copy (id object, size_t extraBytes);
+
+/* Dispose of an object. This method calls the appropriate C++
+ destructors on appropriate C++ instance variables of the instance
+ (if any) (TODO: This is not implemented yet), then frees the memory
+ for the instance. */
+objc_EXPORT id object_dispose (id object);
+
+/* Return the name of the class of 'object'. If 'object' is 'nil',
+ returns "Nil". */
+objc_EXPORT const char * object_getClassName (id object);
+
+/* Change the class of object to be class_. Return the previous class
+ of object. This is currently not really thread-safe. */
+objc_EXPORT Class object_setClass (id object, Class class_);
+
+
+/** Implementation: the following functions are in ivars.c. */
+
+/* Return an instance variable given the class and the instance
+ variable name. This is an expensive function to call, so try to
+ reuse the returned Ivar if you can. */
+objc_EXPORT Ivar class_getInstanceVariable (Class class_, const char *name);
+
+/* Return a class variable given the class and the class variable
+ name. This is an expensive function to call, so try to reuse the
+ returned Ivar if you can.
+
+ This function always returns NULL since class variables are
+ currently unavailable in Objective-C. */
+objc_EXPORT Ivar class_getClassVariable (Class class_, const char *name);
+
+/* If the object was created in class_createInstance() with some
+ extraBytes, returns a pointer to them. If it was not, then the
+ returned pointer may make no sense. */
+objc_EXPORT void * object_getIndexedIvars (id object);
+
+/* Get the value of an instance variable of type 'id'. The function
+ returns the instance variable. To get the value of the instance
+ variable, you should pass as 'returnValue' a pointer to an 'id';
+ the value will be copied there. Note that 'returnValue' is really
+ a 'void *', not a 'void **'. This function really works only with
+ instance variables of type 'id'; for other types of instance
+ variables, access directly the data at (char *)object +
+ ivar_getOffset (ivar). */
+objc_EXPORT Ivar object_getInstanceVariable (id object, const char *name, void **returnValue);
+
+/* Set the value of an instance variable. The value to set is passed
+ in 'newValue' (which really is an 'id', not a 'void *'). The
+ function returns the instance variable. This function really works
+ only with instance variables of type 'id'; for other types of
+ instance variables, access directly the data at (char *)object +
+ ivar_getOffset (ivar). */
+objc_EXPORT Ivar object_setInstanceVariable (id object, const char *name, void *newValue);
+
+/* Get the value of an instance variable of type 'id' of the object
+ 'object'. This is faster than object_getInstanceVariable if you
+ already have the instance variable because it avoids the expensive
+ call to class_getInstanceVariable that is done by
+ object_getInstanceVariable. */
+objc_EXPORT id object_getIvar (id object, Ivar variable);
+
+/* Set the value of an instance variable of type 'id' of the object
+ 'object'. This is faster than object_setInstanceVariable if you
+ already have the instance variable because it avoids the expensive
+ call to class_getInstanceVariable that is done by
+ object_setInstanceVariable. */
+objc_EXPORT void object_setIvar (id object, Ivar variable, id value);
+
+/* Return the name of the instance variable. Return NULL if
+ 'variable' is NULL. */
+objc_EXPORT const char * ivar_getName (Ivar variable);
+
+/* Return the offset of the instance variable from the start of the
+ object data. Return 0 if 'variable' is NULL. */
+objc_EXPORT ptrdiff_t ivar_getOffset (Ivar variable);
+
+/* Return the type encoding of the variable. Return NULL if
+ 'variable' is NULL. */
+objc_EXPORT const char * ivar_getTypeEncoding (Ivar variable);
+
+/* Return all the instance variables of the class. The return value
+ of the function is a pointer to an area, allocated with malloc(),
+ that contains all the instance variables of the class. It does not
+ include instance variables of superclasses. The list is terminated
+ by NULL. Optionally, if you pass a non-NULL
+ 'numberOfReturnedIvars' pointer, the unsigned int that it points to
+ will be filled with the number of instance variables returned.
+ Return NULL for classes still in construction (ie, allocated using
+ objc_allocatedClassPair() but not yet registered with the runtime
+ using objc_registerClassPair()). */
+objc_EXPORT Ivar * class_copyIvarList (Class class_, unsigned int *numberOfReturnedIvars);
+
+/* Add an instance variable with name 'ivar_name' to class 'class_',
+ where 'class_' is a class in construction that has been created
+ using objc_allocateClassPair() and has not been registered with the
+ runtime using objc_registerClassPair() yet. You can not add
+ instance variables to classes already registered with the runtime.
+ 'size' is the size of the instance variable, 'log_2_of_alignment'
+ the alignment as a power of 2 (so 0 means alignment to a 1 byte
+ boundary, 1 means alignment to a 2 byte boundary, 2 means alignment
+ to a 4 byte boundary, etc), and 'type' the type encoding of the
+ variable type. You can use sizeof(), log2(__alignof__()) and
+ @encode() to determine the right 'size', 'alignment' and 'type' for
+ your instance variable. For example, to add an instance variable
+ name "my_variable" and of type 'id', you can use:
+
+ class_addIvar (class, "my_variable", sizeof (id), log2 ( __alignof__ (id)),
+ @encode (id));
+
+ Return YES if the variable was added, and NO if not. In
+ particular, return NO if 'class_' is Nil, or a meta-class or a
+ class not in construction. Return Nil also if 'ivar_name' or
+ 'type' is NULL, or 'size' is 0.
+ */
+objc_EXPORT BOOL class_addIvar (Class class_, const char * ivar_name, size_t size,
+ unsigned char log_2_of_alignment, const char *type);
+
+/* Return the name of the property. Return NULL if 'property' is
+ NULL. */
+objc_EXPORT const char * property_getName (Property property);
+
+/* Return the attributes of the property as a string. Return NULL if
+ 'property' is NULL. */
+objc_EXPORT const char * property_getAttributes (Property property);
+
+/* Return the property with name 'propertyName' of the class 'class_'.
+ This function returns NULL if the required property can not be
+ found. Return NULL if 'class_' or 'propertyName' is NULL.
+
+ Note that the traditional ABI does not store the list of properties
+ of a class in a compiled module, so the traditional ABI will always
+ return NULL. */
+objc_EXPORT Property class_getProperty (Class class_, const char *propertyName);
+
+/* Return all the properties of the class. The return value
+ of the function is a pointer to an area, allocated with malloc(),
+ that contains all the properties of the class. It does not
+ include properties of superclasses. The list is terminated
+ by NULL. Optionally, if you pass a non-NULL
+ 'numberOfReturnedIvars' pointer, the unsigned int that it points to
+ will be filled with the number of properties returned.
+
+ Note that the traditional ABI does not store the list of properties
+ of a class in a compiled module, so the traditional ABI will always
+ return an empty list. */
+objc_EXPORT Property * class_copyPropertyList
+(Class class_, unsigned int *numberOfReturnedProperties);
+
+/* Return the ivar layout for class 'class_'.
+
+ At the moment this function always returns NULL. */
+objc_EXPORT const char * class_getIvarLayout (Class class_);
+
+/* Return the weak ivar layout for class 'class_'.
+
+ At the moment this function always returns NULL. */
+objc_EXPORT const char * class_getWeakIvarLayout (Class class_);
+
+/* Set the ivar layout for class 'class_'.
+
+ At the moment, this function does nothing. */
+objc_EXPORT void class_setIvarLayout (Class class_, const char *layout);
+
+/* Set the weak ivar layout for class 'class_'.
+
+ At the moment, this function does nothing. With the GNU runtime,
+ you should use class_ivar_set_gcinvisible () to hide variables from
+ the Garbage Collector. */
+objc_EXPORT void class_setWeakIvarLayout (Class class_, const char *layout);
+
+
+/** Implementation: the following functions are in class.c. */
+
+/* Compatibility Note: The Apple/NeXT runtime does not have
+ objc_get_unknown_class_handler and
+ objc_setGetUnknownClassHandler(). They provide functionality that
+ the traditional GNU Objective-C Runtime API used to provide via the
+ _objc_lookup_class hook. */
+
+/* An 'objc_get_unknown_class_handler' function is used by
+ objc_getClass() to get a class that is currently unknown to the
+ compiler. You could use it for example to have the class loaded by
+ dynamically loading a library. 'class_name' is the name of the
+ class. The function should return the Class object if it manages to
+ load the class, and Nil if not. */
+typedef Class (*objc_get_unknown_class_handler)(const char *class_name);
+
+/* Sets a new handler function for getting unknown classes (to be used
+ by objc_getClass () and related), and returns the previous one.
+ This function is not safe to call in a multi-threaded environment
+ because other threads may be trying to use the get unknown class
+ handler while you change it! */
+objc_EXPORT
+objc_get_unknown_class_handler
+objc_setGetUnknownClassHandler (objc_get_unknown_class_handler new_handler);
+
+/* Return the class with name 'name', if it is already registered with
+ the runtime. If it is not registered, and
+ objc_setGetUnknownClassHandler() has been called to set a handler
+ for unknown classes, the handler is called to give it a chance to
+ load the class in some other way. If the class is not known to the
+ runtime and the handler is not set or returns Nil, objc_getClass()
+ returns Nil. */
+objc_EXPORT Class objc_getClass (const char *name);
+
+/* Return the class with name 'name', if it is already registered with
+ the runtime. Return Nil if not. This function does not call the
+ objc_get_unknown_class_handler function if the class is not
+ found. */
+objc_EXPORT Class objc_lookUpClass (const char *name);
+
+/* Return the meta class associated to the class with name 'name', if
+ it is already registered with the runtime. First, it finds the
+ class using objc_getClass(). Then, it returns the associated meta
+ class. If the class could not be found using objc_getClass(),
+ returns Nil. */
+objc_EXPORT Class objc_getMetaClass (const char *name);
+
+/* This is identical to objc_getClass(), but if the class is not found,
+ it aborts the process instead of returning Nil. */
+objc_EXPORT Class objc_getRequiredClass (const char *name);
+
+/* If 'returnValue' is NULL, 'objc_getClassList' returns the number of
+ classes currently registered with the runtime. If 'returnValue' is
+ not NULL, it should be a (Class *) pointer to an area of memory
+ which can contain up to 'maxNumberOfClassesToReturn' Class records.
+ 'objc_getClassList' will fill the area pointed to by 'returnValue'
+ with all the Classes registered with the runtime (or up to
+ maxNumberOfClassesToReturn if there are more than
+ maxNumberOfClassesToReturn). The function return value is the
+ number of classes actually returned in 'returnValue'. */
+objc_EXPORT int objc_getClassList (Class *returnValue, int maxNumberOfClassesToReturn);
+
+/* Compatibility Note: The Apple/NeXT runtime also has
+
+ Class objc_getFutureClass (const char *name);
+ void objc_setFutureClass (Class class_, const char *name);
+
+ the documentation is unclear on what they are supposed to do, and
+ the GNU Objective-C Runtime currently does not provide them. */
+
+/* Return the name of the class 'class_', or the string "nil" if the
+ class_ is Nil. */
+objc_EXPORT const char * class_getName (Class class_);
+
+/* Return YES if 'class_' is a meta class, and NO if not. If 'class_'
+ is Nil, return NO. */
+objc_EXPORT BOOL class_isMetaClass (Class class_);
+
+/* Return the superclass of 'class_'. If 'class_' is Nil, or it is a
+ root class, return Nil. This function also works if 'class_' is a
+ class being constructed, that is, a class returned by
+ objc_allocateClassPair() but before it has been registered with the
+ runtime using objc_registerClassPair(). */
+objc_EXPORT Class class_getSuperclass (Class class_);
+
+/* Return the 'version' number of the class, which is an integer that
+ can be used to track changes in the class API, methods and
+ variables. If class_ is Nil, return 0. If class_ is not Nil, the
+ version is 0 unless class_setVersion() has been called to set a
+ different one.
+
+ Please note that internally the version is a long, but the API only
+ allows you to set and retrieve int values. */
+objc_EXPORT int class_getVersion (Class class_);
+
+/* Set the 'version' number of the class, which is an integer that can
+ be used to track changes in the class API, methods and variables.
+ If 'class_' is Nil, does nothing.
+
+ This is typically used internally by "Foundation" libraries such as
+ GNUstep Base to support serialization / deserialization of objects
+ that work across changes in the classes. If you are using such a
+ library, you probably want to use their versioning API, which may
+ be based on this one, but is integrated with the rest of the
+ library.
+
+ Please note that internally the version is a long, but the API only
+ allows you to set and retrieve int values. */
+objc_EXPORT void class_setVersion (Class class_, int version);
+
+/* Return the size in bytes (a byte is the size of a char) of an
+ instance of the class. If class_ is Nil, return 0; else it return
+ a non-zero number (since the 'isa' instance variable is required
+ for all classes). */
+objc_EXPORT size_t class_getInstanceSize (Class class_);
+
+/* Change the implementation of the method. It also searches all
+ classes for any class implementing the method, and replaces the
+ existing implementation with the new one. For that to work,
+ 'method' must be a method returned by class_getInstanceMethod() or
+ class_getClassMethod() as the matching is done by comparing the
+ pointers; in that case, only the implementation in the class is
+ modified. Return the previous implementation that has been
+ replaced. If method or implementation is NULL, do nothing and
+ return NULL. */
+objc_EXPORT IMP
+method_setImplementation (Method method, IMP implementation);
+
+/* Swap the implementation of two methods in a single, atomic
+ operation. This is equivalent to getting the implementation of
+ each method and then calling method_setImplementation() on the
+ other one. For this to work, the two methods must have been
+ returned by class_getInstanceMethod() or class_getClassMethod().
+ If 'method_a' or 'method_b' is NULL, do nothing. */
+objc_EXPORT void
+method_exchangeImplementations (Method method_a, Method method_b);
+
+/* Create a new class/meta-class pair. This function is called to
+ create a new class at runtime. The class is created with
+ superclass 'superclass' (use 'Nil' to create a new root class) and
+ name 'class_name'. 'extraBytes' can be used to specify some extra
+ space for indexed variables to be added at the end of the class and
+ meta-class objects (it is recommended that you set extraBytes to
+ 0). Once you have created the class, it is not usable yet. You
+ need to add any instance variables (by using class_addIvar()), any
+ instance methods (by using class_addMethod()) and any class methods
+ (by using class_addMethod() on the meta-class, as in
+ class_addMethod (object_getClass (class), method)) that are
+ required, and then you need to call objc_registerClassPair() to
+ activate the class. If you need to create a hierarchy of classes,
+ you need to create and register them one at a time. You can not
+ create a new class using another class in construction as
+ superclass. Return Nil if 'class-name' is NULL or if a class with
+ that name already exists or 'superclass' is a class still in
+ construction.
+
+ Implementation Note: in the GNU runtime, allocating a class pair
+ only creates the structures for the class pair, but does not
+ register anything with the runtime. The class is registered with
+ the runtime only when objc_registerClassPair() is called. In
+ particular, if a class is in construction, objc_getClass() will not
+ find it, the superclass will not know about it,
+ class_getSuperclass() will return Nil and another thread may
+ allocate a class pair with the same name; the conflict will only be
+ detected when the classes are registered with the runtime.
+ */
+objc_EXPORT Class
+objc_allocateClassPair (Class super_class, const char *class_name,
+ size_t extraBytes);
+
+/* Register a class pair that was created with
+ objc_allocateClassPair(). After you register a class, you can no
+ longer make changes to its instance variables, but you can start
+ creating instances of it. Do nothing if 'class_' is NULL or if it
+ is not a class allocated by objc_allocateClassPair() and still in
+ construction. */
+objc_EXPORT void
+objc_registerClassPair (Class class_);
+
+/* Dispose of a class pair created using objc_allocateClassPair().
+ Call this function if you started creating a new class with
+ objc_allocateClassPair() but then want to abort the process. You
+ should not access 'class_' after calling this method. Note that if
+ 'class_' has already been registered with the runtime via
+ objc_registerClassPair(), this function does nothing; you can only
+ dispose of class pairs that are still being constructed. Do
+ nothing if class is 'Nil' or if 'class_' is not a class being
+ constructed. */
+objc_EXPORT void
+objc_disposeClassPair (Class class_);
+
+/* Compatibility Note: The Apple/NeXT runtime has the function
+ objc_duplicateClass () but it's undocumented. The GNU runtime does
+ not have it. */
+
+
+/** Implementation: the following functions are in sendmsg.c. */
+
+/* Return the instance method with selector 'selector' of class
+ 'class_', or NULL if the class (or one of its superclasses) does
+ not implement the method. Return NULL if class_ is Nil or selector
+ is NULL. Calling this function may trigger a call to
+ +resolveInstanceMethod:, but does not return a forwarding
+ function. */
+objc_EXPORT Method class_getInstanceMethod (Class class_, SEL selector);
+
+/* Return the class method with selector 'selector' of class 'class_',
+ or NULL if the class (or one of its superclasses) does not
+ implement the method. Return NULL if class_ is Nil or selector is
+ NULL. Calling this function may trigger a call to
+ +resolveClassMethod:, but does not return a forwarding
+ function. */
+objc_EXPORT Method class_getClassMethod (Class class_, SEL selector);
+
+/* Return the IMP (pointer to the function implementing a method) for
+ the instance method with selector 'selector' in class 'class_'.
+ This is the same routine that is used while messaging, and should
+ be very fast. Note that you most likely would need to cast the
+ return function pointer to a function pointer with the appropriate
+ arguments and return type before calling it. To get a class
+ method, you can pass the meta-class as the class_ argument (ie, use
+ class_getMethodImplementation (object_getClass (class_),
+ selector)). Return NULL if class_ is Nil or selector is NULL.
+ This function first looks for an existing method; if it is not
+ found, it calls +resolveClassMethod: or +resolveInstanceMethod:
+ (depending on whether a class or instance method is being looked
+ up) if it is implemented. If the method returns YES, then it tries
+ the look up again (the assumption being that +resolveClassMethod:
+ or resolveInstanceMethod: will add the method using
+ class_addMethod()). If it is still not found, it returns a
+ forwarding function. */
+objc_EXPORT IMP class_getMethodImplementation (Class class_, SEL selector);
+
+/* Compatibility Note: the Apple/NeXT runtime has the function
+ class_getMethodImplementation_stret () which currently does not
+ exist on the GNU runtime because the messaging implementation is
+ different. */
+
+/* Return YES if class 'class_' has an instance method implementing
+ selector 'selector', and NO if not. Return NO if class_ is Nil or
+ selector is NULL. If you need to check a class method, use the
+ meta-class as the class_ argument (ie, use class_respondsToSelector
+ (object_getClass (class_), selector)). */
+objc_EXPORT BOOL class_respondsToSelector (Class class_, SEL selector);
+
+/* Add a method to a class. Use this function to add a new method to
+ a class (potentially overriding a method with the same selector in
+ the superclass); if you want to modify an existing method, use
+ method_setImplementation() instead (or class_replaceMethod ()).
+ This method adds an instance method to 'class_'; to add a class
+ method, get the meta class first, then add the method to the meta
+ class, that is, use
+
+ class_addMethod (object_getClass (class_), selector,
+ implementation, type);
+
+ Return YES if the method was added, and NO if not. Do nothing if
+ one of the arguments is NULL. */
+objc_EXPORT BOOL class_addMethod (Class class_, SEL selector, IMP implementation,
+ const char *method_types);
+
+/* Replace a method in a class. If the class already have a method
+ with this 'selector', find it and use method_setImplementation() to
+ replace the implementation with 'implementation' (method_types is
+ ignored in that case). If the class does not already have a method
+ with this 'selector', call 'class_addMethod() to add it.
+
+ Return the previous implementation of the method, or NULL if none
+ was found. Return NULL if any of the arguments is NULL. */
+objc_EXPORT IMP class_replaceMethod (Class class_, SEL selector, IMP implementation,
+ const char *method_types);
+
+
+/** Implementation: the following functions are in methods.c. */
+
+/* Return the selector for method 'method'. Return NULL if 'method'
+ is NULL.
+
+ This function is misnamed; it should be called
+ 'method_getSelector'. To get the actual name, get the selector,
+ then the name from the selector (ie, use sel_getName
+ (method_getName (method))). */
+objc_EXPORT SEL method_getName (Method method);
+
+/* Return the IMP of the method. Return NULL if 'method' is NULL. */
+objc_EXPORT IMP method_getImplementation (Method method);
+
+/* Return the type encoding of the method. Return NULL if 'method' is
+ NULL. */
+objc_EXPORT const char * method_getTypeEncoding (Method method);
+
+/* Return a method description for the method. Return NULL if
+ 'method' is NULL. */
+objc_EXPORT struct objc_method_description * method_getDescription (Method method);
+
+/* Return all the instance methods of the class. The return value of
+ the function is a pointer to an area, allocated with malloc(), that
+ contains all the instance methods of the class. It does not
+ include instance methods of superclasses. The list is terminated
+ by NULL. Optionally, if you pass a non-NULL
+ 'numberOfReturnedMethods' pointer, the unsigned int that it points
+ to will be filled with the number of instance methods returned. To
+ get the list of class methods, pass the meta-class in the 'class_'
+ argument, (ie, use class_copyMethodList (object_getClass (class_),
+ &numberOfReturnedMethods)). */
+objc_EXPORT Method * class_copyMethodList (Class class_, unsigned int *numberOfReturnedMethods);
+
+
+/** Implementation: the following functions are in encoding.c. */
+
+/* Return the number of arguments that the method 'method' expects.
+ Note that all methods need two implicit arguments ('self' for the
+ receiver, and '_cmd' for the selector). Return 0 if 'method' is
+ NULL. */
+objc_EXPORT unsigned int method_getNumberOfArguments (Method method);
+
+/* Return the string encoding for the return type of method 'method'.
+ The string is a standard zero-terminated string in an area of
+ memory allocated with malloc(); you should free it with free() when
+ you finish using it. Return an empty string if method is NULL. */
+objc_EXPORT char * method_copyReturnType (Method method);
+
+/* Return the string encoding for the argument type of method
+ 'method', argument number 'argumentNumber' ('argumentNumber' is 0
+ for self, 1 for _cmd, and 2 or more for the additional arguments if
+ any). The string is a standard zero-terminated string in an area
+ of memory allocated with malloc(); you should free it with free()
+ when you finish using it. Return an empty string if method is NULL
+ or if 'argumentNumber' refers to a non-existing argument. */
+objc_EXPORT char * method_copyArgumentType (Method method, unsigned int argumentNumber);
+
+/* Return the string encoding for the return type of method 'method'.
+ The string is returned by copying it into the supplied
+ 'returnValue' string, which is of size 'returnValueSize'. No more
+ than 'returnValueSize' characters are copied; if the encoding is
+ smaller than 'returnValueSize', the rest of 'returnValue' is filled
+ with zeros. If it is bigger, it is truncated (and would not be
+ zero-terminated). You should supply a big enough
+ 'returnValueSize'. If the method is NULL, returnValue is set to a
+ string of zeros. */
+objc_EXPORT void method_getReturnType (Method method, char *returnValue,
+ size_t returnValueSize);
+
+/* Return the string encoding for the argument type of method
+ 'method', argument number 'argumentNumber' ('argumentNumber' is 0
+ for self, 1 for _cmd, and 2 or more for the additional arguments if
+ any). The string is returned by copying it into the supplied
+ 'returnValue' string, which is of size 'returnValueSize'. No more
+ than 'returnValueSize' characters are copied; if the encoding is
+ smaller than 'returnValueSize', the rest of 'returnValue' is filled
+ with zeros. If it is bigger, it is truncated (and would not be
+ zero-terminated). You should supply a big enough
+ 'returnValueSize'. If the method is NULL, returnValue is set to a
+ string of zeros. */
+objc_EXPORT void method_getArgumentType (Method method, unsigned int argumentNumber,
+ char *returnValue, size_t returnValueSize);
+
+
+/** Implementation: the following functions are in protocols.c. */
+
+/* Return the protocol with name 'name', or nil if it the protocol is
+ not known to the runtime. */
+objc_EXPORT Protocol *objc_getProtocol (const char *name);
+
+/* Return all the protocols known to the runtime. The return value of
+ the function is a pointer to an area, allocated with malloc(), that
+ contains all the protocols known to the runtime; the list is
+ terminated by NULL. You should free this area using free() once
+ you no longer need it. Optionally, if you pass a non-NULL
+ 'numberOfReturnedProtocols' pointer, the unsigned int that it
+ points to will be filled with the number of protocols returned. If
+ there are no protocols known to the runtime, NULL is returned. */
+objc_EXPORT Protocol **objc_copyProtocolList (unsigned int *numberOfReturnedProtocols);
+
+/* Add a protocol to a class, and return YES if it was done
+ succesfully, and NO if not. At the moment, NO should only happen
+ if class_ or protocol are nil, if the protocol is not a Protocol
+ object or if the class already conforms to the protocol. */
+objc_EXPORT BOOL class_addProtocol (Class class_, Protocol *protocol);
+
+/* Return YES if the class 'class_' conforms to Protocol 'protocol',
+ and NO if not. This function does not check superclasses; if you
+ want to check for superclasses (in the way that [NSObject
+ +conformsToProtocol:] does) you need to iterate over the class
+ hierarchy using class_getSuperclass(), and call
+ class_conformsToProtocol() for each of them. */
+objc_EXPORT BOOL class_conformsToProtocol (Class class_, Protocol *protocol);
+
+/* Return all the protocols that the class conforms to. The return
+ value of the function is a pointer to an area, allocated with
+ malloc(), that contains all the protocols formally adopted by the
+ class. It does not include protocols adopted by superclasses. The
+ list is terminated by NULL. Optionally, if you pass a non-NULL
+ 'numberOfReturnedProtocols' pointer, the unsigned int that it
+ points to will be filled with the number of protocols returned.
+ This function does not return protocols that superclasses conform
+ to. */
+objc_EXPORT Protocol **class_copyProtocolList (Class class_, unsigned int *numberOfReturnedProtocols);
+
+/* Return YES if protocol 'protocol' conforms to protocol
+ 'anotherProtocol', and NO if not. Note that if one of the two
+ protocols is nil, it returns NO. */
+objc_EXPORT BOOL protocol_conformsToProtocol (Protocol *protocol, Protocol *anotherProtocol);
+
+/* Return YES if protocol 'protocol' is the same as protocol
+ 'anotherProtocol', and 'NO' if not. Note that it returns YES if
+ the two protocols are both nil. */
+objc_EXPORT BOOL protocol_isEqual (Protocol *protocol, Protocol *anotherProtocol);
+
+/* Return the name of protocol 'protocol'. If 'protocol' is nil or is
+ not a Protocol, return NULL. */
+objc_EXPORT const char *protocol_getName (Protocol *protocol);
+
+/* Return the method description for the method with selector
+ 'selector' in protocol 'protocol'; if 'requiredMethod' is YES, the
+ function searches the list of required methods; if NO, the list of
+ optional methods. If 'instanceMethod' is YES, the function search
+ for an instance method; if NO, for a class method. If there is no
+ matching method, an objc_method_description structure with both
+ name and types set to NULL is returned. This function will only
+ find methods that are directly declared in the protocol itself, not
+ in other protocols that this protocol adopts.
+
+ Note that the traditional ABI does not store the list of optional
+ methods of a protocol in a compiled module, so the traditional ABI
+ will always return (NULL, NULL) when requiredMethod == NO. */
+objc_EXPORT struct objc_method_description protocol_getMethodDescription (Protocol *protocol,
+ SEL selector,
+ BOOL requiredMethod,
+ BOOL instanceMethod);
+
+/* Return the method descriptions of all the methods of the protocol.
+ The return value of the function is a pointer to an area, allocated
+ with malloc(), that contains all the method descriptions of the
+ methods of the protocol. It does not recursively include methods
+ of the protocols adopted by this protocol. The list is terminated
+ by a NULL objc_method_description (one with both fields set to
+ NULL). Optionally, if you pass a non-NULL
+ 'numberOfReturnedMethods' pointer, the unsigned int that it points
+ to will be filled with the number of properties returned.
+
+ Note that the traditional ABI does not store the list of optional
+ methods of a protocol in a compiled module, so the traditional ABI
+ will always return an empty list if requiredMethod is set to
+ NO. */
+objc_EXPORT struct objc_method_description *protocol_copyMethodDescriptionList (Protocol *protocol,
+ BOOL requiredMethod,
+ BOOL instanceMethod,
+ unsigned int *numberOfReturnedMethods);
+
+/* Return the property with name 'propertyName' of the protocol
+ 'protocol'. If 'requiredProperty' is YES, the function searches
+ the list of required properties; if NO, the list of optional
+ properties. If 'instanceProperty' is YES, the function searches
+ the list of instance properties; if NO, the list of class
+ properties. At the moment, optional properties and class
+ properties are not part of the Objective-C language, so both
+ 'requiredProperty' and 'instanceProperty' should be set to YES.
+ This function returns NULL if the required property can not be
+ found.
+
+ Note that the traditional ABI does not store the list of properties
+ of a protocol in a compiled module, so the traditional ABI will
+ always return NULL. */
+objc_EXPORT Property protocol_getProperty (Protocol *protocol, const char *propertyName,
+ BOOL requiredProperty, BOOL instanceProperty);
+
+/* Return all the properties of the protocol. The return value of the
+ function is a pointer to an area, allocated with malloc(), that
+ contains all the properties of the protocol. It does not
+ recursively include properties of the protocols adopted by this
+ protocol. The list is terminated by NULL. Optionally, if you pass
+ a non-NULL 'numberOfReturnedProperties' pointer, the unsigned int
+ that it points to will be filled with the number of properties
+ returned.
+
+ Note that the traditional ABI does not store the list of properties
+ of a protocol in a compiled module, so the traditional ABI will
+ always return NULL and store 0 in numberOfReturnedProperties. */
+objc_EXPORT Property *protocol_copyPropertyList (Protocol *protocol, unsigned int *numberOfReturnedProperties);
+
+/* Return all the protocols that the protocol conforms to. The return
+ value of the function is a pointer to an area, allocated with
+ malloc(), that contains all the protocols formally adopted by the
+ protocol. It does not recursively include protocols adopted by the
+ protocols adopted by this protocol. The list is terminated by
+ NULL. Optionally, if you pass a non-NULL
+ 'numberOfReturnedProtocols' pointer, the unsigned int that it
+ points to will be filled with the number of protocols returned. */
+objc_EXPORT Protocol **protocol_copyProtocolList (Protocol *protocol, unsigned int *numberOfReturnedProtocols);
+
+
+/** Implementation: the following hook is in init.c. */
+
+/* This is a hook which is called by __objc_exec_class every time a
+ class or a category is loaded into the runtime. This may e.g. help
+ a dynamic loader determine the classes that have been loaded when
+ an object file is dynamically linked in. */
+objc_EXPORT void (*_objc_load_callback)(Class _class, struct objc_category *category);
+
+
+/** Implementation: the following functions are in objc-foreach.c. */
+
+/* 'objc_enumerationMutation()' is called when a collection is
+ mutated while being "fast enumerated". That is a hard error, and
+ objc_enumerationMutation is called to deal with it. 'collection'
+ is the collection object that was mutated during an enumeration.
+
+ objc_enumerationMutation() will invoke the mutation handler if any
+ is set. Then, it will abort the program.
+
+ Compatibility note: the Apple runtime will not abort the program
+ after calling the mutation handler. */
+objc_EXPORT void objc_enumerationMutation (id collection);
+
+/* 'objc_set_enumeration_mutation_handler' can be used to set a
+ function that will be called (instead of aborting) when a fast
+ enumeration is mutated during enumeration. The handler will be
+ called with the 'collection' being mutated as the only argument and
+ it should not return; it should either exit the program, or could
+ throw an exception. The recommended implementation is to throw an
+ exception - the user can then use exception handlers to deal with
+ it.
+
+ This function is not thread safe (other threads may be trying to
+ invoke the enumeration mutation handler while you are changing it!)
+ and should be called during during the program initialization
+ before threads are started. It is mostly reserved for "Foundation"
+ libraries; in the case of GNUstep, GNUstep Base may be using this
+ function to improve the standard enumeration mutation handling.
+ You probably shouldn't use this function unless you are writing
+ your own Foundation library. */
+objc_EXPORT void objc_setEnumerationMutationHandler (void (*handler)(id));
+
+/* This structure (used during fast enumeration) is automatically
+ defined by the compiler (it is as if this definition was always
+ included in all Objective-C files). Note that it is usually
+ defined again with the name of NSFastEnumeration by "Foundation"
+ libraries such as GNUstep Base. And if NSFastEnumeration is
+ defined, the compiler will use it instead of
+ __objcFastEnumerationState when doing fast enumeration. */
+/*
+struct __objcFastEnumerationState
+{
+ unsigned long state;
+ id *itemsPtr;
+ unsigned long *mutationsPtr;
+ unsigned long extra[5];
+};
+*/
+
+
+/* Compatibility Note: The Apple/NeXT runtime has the functions
+ objc_copyImageNames (), class_getImageName () and
+ objc_copyClassNamesForImage () but they are undocumented. The GNU
+ runtime does not have them at the moment. */
+
+/* Compatibility Note: The Apple/NeXT runtime has the functions
+ objc_setAssociatedObject (), objc_getAssociatedObject (),
+ objc_removeAssociatedObjects () and the objc_AssociationPolicy type
+ and related enum. The GNU runtime does not have them yet.
+ TODO: Implement them. */
+
+/* Compatibility Note: The Apple/NeXT runtime has the function
+ objc_setForwardHandler (). The GNU runtime does not have it
+ because messaging (and, in particular, forwarding) works in a
+ different (incompatible) way with the GNU runtime. If you need to
+ customize message forwarding at the Objective-C runtime level (that
+ is, if you are implementing your own "Foundation" library such as
+ GNUstep Base on top of the Objective-C runtime), in objc/message.h
+ there are hooks (that work in the framework of the GNU runtime) to
+ do so. */
+
+
+/** Implementation: the following functions are in memory.c. */
+
+/* Traditional GNU Objective-C Runtime functions that are used for
+ memory allocation and disposal. These functions are used in the
+ same way as you use malloc, realloc, calloc and free and make sure
+ that memory allocation works properly with the garbage
+ collector.
+
+ Compatibility Note: these functions are not available with the
+ Apple/NeXT runtime. */
+
+objc_EXPORT void *objc_malloc(size_t size);
+
+/* FIXME: Shouldn't the following be called objc_malloc_atomic ? The
+ GC function is GC_malloc_atomic() which makes sense.
+ */
+objc_EXPORT void *objc_atomic_malloc(size_t size);
+
+objc_EXPORT void *objc_realloc(void *mem, size_t size);
+
+objc_EXPORT void *objc_calloc(size_t nelem, size_t size);
+
+objc_EXPORT void objc_free(void *mem);
+
+
+/** Implementation: the following functions are in gc.c. */
+
+/* The GNU Objective-C Runtime has a different implementation of
+ garbage collection.
+
+ Compatibility Note: these functions are not available with the
+ Apple/NeXT runtime. */
+
+/* Mark the instance variable as inaccessible to the garbage
+ collector. */
+objc_EXPORT void class_ivar_set_gcinvisible (Class _class,
+ const char* ivarname,
+ BOOL gcInvisible);
+
+
+/** Implementation: the following functions are in encoding.c. */
+
+/* Traditional GNU Objective-C Runtime functions that are currently
+ used to implement method forwarding.
+
+ Compatibility Note: these functions are not available with the
+ Apple/NeXT runtime. */
+
+/* Return the size of a variable which has the specified 'type'
+ encoding. */
+objc_EXPORT int objc_sizeof_type (const char *type);
+
+/* Return the align of a variable which has the specified 'type'
+ encoding. */
+objc_EXPORT int objc_alignof_type (const char *type);
+
+/* Return the aligned size of a variable which has the specified
+ 'type' encoding. The aligned size is the size rounded up to the
+ nearest alignment. */
+objc_EXPORT int objc_aligned_size (const char *type);
+
+/* Return the promoted size of a variable which has the specified
+ 'type' encoding. This is the size rounded up to the nearest
+ integral of the wordsize, taken to be the size of a void *. */
+objc_EXPORT int objc_promoted_size (const char *type);
+
+
+/* The following functions are used when parsing the type encoding of
+ methods, to skip over parts that are ignored. They take as
+ argument a pointer to a location inside the type encoding of a
+ method (which is a string) and return a new pointer, pointing to a
+ new location inside the string after having skipped the unwanted
+ information. */
+
+/* Skip some type qualifiers (_C_CONST, _C_IN, etc). These may
+ eventually precede typespecs occurring in method prototype
+ encodings. */
+objc_EXPORT const char *objc_skip_type_qualifiers (const char *type);
+
+/* Skip one typespec element (_C_CLASS, _C_SEL, etc). If the typespec
+ is prepended by type qualifiers, these are skipped as well. */
+objc_EXPORT const char *objc_skip_typespec (const char *type);
+
+/* Skip an offset. */
+objc_EXPORT const char *objc_skip_offset (const char *type);
+
+/* Skip an argument specification (ie, skipping a typespec, which may
+ include qualifiers, and an offset too). */
+objc_EXPORT const char *objc_skip_argspec (const char *type);
+
+/* Read type qualifiers (_C_CONST, _C_IN, etc) from string 'type'
+ (stopping at the first non-type qualifier found) and return an
+ unsigned int which is the logical OR of all the corresponding flags
+ (_F_CONST, _F_IN etc). */
+objc_EXPORT unsigned objc_get_type_qualifiers (const char *type);
+
+
+/* Note that the following functions work for very simple structures,
+ but get easily confused by more complicated ones (for example,
+ containing vectors). A better solution is required. These
+ functions are likely to change in the next GCC release. */
+
+/* The following three functions can be used to determine how a
+ structure is laid out by the compiler. For example:
+
+ struct objc_struct_layout layout;
+ int i;
+
+ objc_layout_structure (type, &layout);
+ while (objc_layout_structure_next_member (&layout))
+ {
+ int position, align;
+ const char *type;
+
+ objc_layout_structure_get_info (&layout, &position, &align, &type);
+ printf ("element %d has offset %d, alignment %d\n",
+ i++, position, align);
+ }
+
+ These functions are used by objc_sizeof_type and objc_alignof_type
+ functions to compute the size and alignment of structures. The
+ previous method of computing the size and alignment of a structure
+ was not working on some architectures, particulary on AIX, and in
+ the presence of bitfields inside the structure. */
+struct objc_struct_layout
+{
+ const char *original_type;
+ const char *type;
+ const char *prev_type;
+ unsigned int record_size;
+ unsigned int record_align;
+};
+
+objc_EXPORT void objc_layout_structure (const char *type,
+ struct objc_struct_layout *layout);
+objc_EXPORT BOOL objc_layout_structure_next_member (struct objc_struct_layout *layout);
+objc_EXPORT void objc_layout_finish_structure (struct objc_struct_layout *layout,
+ unsigned int *size,
+ unsigned int *align);
+objc_EXPORT void objc_layout_structure_get_info (struct objc_struct_layout *layout,
+ unsigned int *offset,
+ unsigned int *align,
+ const char **type);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif
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