@copying
@c man begin COPYRIGHT
-Copyright @copyright{} 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996,
-1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
-2008, 2009, 2010, 2011
-Free Software Foundation, Inc.
+Copyright @copyright{} 1987-2016 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
converted to the execution character set, just like unescaped
characters.
-Unless the experimental @option{-fextended-identifiers} option is used,
-GCC does not permit the use of characters outside the ASCII range, nor
-@samp{\u} and @samp{\U} escapes, in identifiers. Even with that
-option, characters outside the ASCII range can only be specified with
-the @samp{\u} and @samp{\U} escapes, not used directly in identifiers.
+In identifiers, characters outside the ASCII range can only be
+specified with the @samp{\u} and @samp{\U} escapes, not used
+directly. If strict ISO C90 conformance is specified with an option
+such as @option{-std=c90}, or @option{-fno-extended-identifiers} is
+used, then those escapes are not permitted in identifiers.
@node Initial processing
@section Initial processing
part of the ``basic source character set'', at the implementation's
discretion (such as accented Latin letters, Greek letters, or Chinese
ideograms). This may be done with an extended character set, or the
-@samp{\u} and @samp{\U} escape sequences. The implementation of this
-feature in GCC is experimental; such characters are only accepted in
-the @samp{\u} and @samp{\U} forms and only if
-@option{-fextended-identifiers} is used.
+@samp{\u} and @samp{\U} escape sequences. GCC only accepts such
+characters in the @samp{\u} and @samp{\U} forms.
As an extension, GCC treats @samp{$} as a letter. This is for
compatibility with some systems, such as VMS, where @samp{$} is commonly
/usr/include
@end smallexample
-For C++ programs, it will also look in @file{/usr/include/g++-v3},
+For C++ programs, it will also look in
+@file{@var{libdir}/../include/c++/@var{version}},
first. In the above, @var{target} is the canonical name of the system
GCC was configured to compile code for; often but not always the same as
the canonical name of the system it runs on. @var{version} is the
version of GCC in use.
-You can add to this list with the @option{-I@var{dir}} command line
+You can add to this list with the @option{-I@var{dir}} command-line
option. All the directories named by @option{-I} are searched, in
left-to-right order, @emph{before} the default directories. The only
exception is when @file{dir} is already searched by default. In
system headers. These directories are determined when GCC is compiled.
There are, however, two ways to make normal headers into system headers.
-The @option{-isystem} command line option adds its argument to the list of
+The @option{-isystem} command-line option adds its argument to the list of
directories to search for headers, just like @option{-I}. Any headers
found in that directory will be considered system headers.
This macro is defined when the C++ compiler is in use. You can use
@code{__cplusplus} to test whether a header is compiled by a C compiler
or a C++ compiler. This macro is similar to @code{__STDC_VERSION__}, in
-that it expands to a version number. A fully conforming implementation
-of the 1998 C++ standard will define this macro to @code{199711L}. The
-GNU C++ compiler is not yet fully conforming, so it uses @code{1}
-instead. It is hoped to complete the implementation of standard C++
-in the near future.
+that it expands to a version number. Depending on the language standard
+selected, the value of the macro is
+@code{199711L} for the 1998 C++ standard,
+@code{201103L} for the 2011 C++ standard,
+@code{201402L} for the 2014 C++ standard,
+or an unspecified value strictly larger than @code{201402L} for the
+experimental languages enabled by @option{-std=c++1z} and
+@option{-std=gnu++1z}.
@item __OBJC__
This macro is defined, with value 1, when the Objective-C compiler is in
you can simply test @code{__GNUC__}. If you need to write code
which depends on a specific version, you must be more careful. Each
time the minor version is increased, the patch level is reset to zero;
-each time the major version is increased (which happens rarely), the
+each time the major version is increased, the
minor version and patch level are reset. If you wish to use the
predefined macros directly in the conditional, you will need to write it
like this:
@item __STRICT_ANSI__
GCC defines this macro if and only if the @option{-ansi} switch, or a
-@option{-std} switch specifying strict conformance to some version of ISO C,
-was specified when GCC was invoked. It is defined to @samp{1}.
+@option{-std} switch specifying strict conformance to some version of ISO C
+or ISO C++, was specified when GCC was invoked. It is defined to @samp{1}.
This macro exists primarily to direct GNU libc's header files to
restrict their definitions to the minimal set found in the 1989 C
standard.
This macro is defined, with value 2, when @option{-fstack-protector-all} is
in use.
+@item __SSP_STRONG__
+This macro is defined, with value 3, when @option{-fstack-protector-strong} is
+in use.
+
+@item __SSP_EXPLICIT__
+This macro is defined, with value 4, when @option{-fstack-protector-explicit} is
+in use.
+
+@item __SANITIZE_ADDRESS__
+This macro is defined, with value 1, when @option{-fsanitize=address}
+or @option{-fsanitize=kernel-address} are in use.
+
@item __TIMESTAMP__
This macro expands to a string constant that describes the date and time
of the last modification of the current source file. The string constant
and swap operations on operands 1, 2, 4, 8 or 16 bytes in length, respectively.
@item __GCC_HAVE_DWARF2_CFI_ASM
-This macro is defined when the compiler is emitting Dwarf2 CFI directives
+This macro is defined when the compiler is emitting DWARF CFI directives
to the assembler. When this is defined, it is possible to emit those same
directives in inline assembly.
the include file @file{math.h} can define the macros
@code{FP_FAST_FMA}, @code{FP_FAST_FMAF}, and @code{FP_FAST_FMAL}
for compatibility with the 1999 C standard.
+
+@item __GCC_IEC_559
+This macro is defined to indicate the intended level of support for
+IEEE 754 (IEC 60559) floating-point arithmetic. It expands to a
+nonnegative integer value. If 0, it indicates that the combination of
+the compiler configuration and the command-line options is not
+intended to support IEEE 754 arithmetic for @code{float} and
+@code{double} as defined in C99 and C11 Annex F (for example, that the
+standard rounding modes and exceptions are not supported, or that
+optimizations are enabled that conflict with IEEE 754 semantics). If
+1, it indicates that IEEE 754 arithmetic is intended to be supported;
+this does not mean that all relevant language features are supported
+by GCC. If 2 or more, it additionally indicates support for IEEE
+754-2008 (in particular, that the binary encodings for quiet and
+signaling NaNs are as specified in IEEE 754-2008).
+
+This macro does not indicate the default state of command-line options
+that control optimizations that C99 and C11 permit to be controlled by
+standard pragmas, where those standards do not require a particular
+default state. It does not indicate whether optimizations respect
+signaling NaN semantics (the macro for that is
+@code{__SUPPORT_SNAN__}). It does not indicate support for decimal
+floating point or the IEEE 754 binary16 and binary128 types.
+
+@item __GCC_IEC_559_COMPLEX
+This macro is defined to indicate the intended level of support for
+IEEE 754 (IEC 60559) floating-point arithmetic for complex numbers, as
+defined in C99 and C11 Annex G. It expands to a nonnegative integer
+value. If 0, it indicates that the combination of the compiler
+configuration and the command-line options is not intended to support
+Annex G requirements (for example, because @option{-fcx-limited-range}
+was used). If 1 or more, it indicates that it is intended to support
+those requirements; this does not mean that all relevant language
+features are supported by GCC.
+
+@item __NO_MATH_ERRNO__
+This macro is defined if @option{-fno-math-errno} is used, or enabled
+by another option such as @option{-ffast-math} or by default.
@end table
@node System-specific Predefined Macros
each target supported by GCC@. This manual, being for all systems and
machines, cannot tell you what their names are, but you can use
@command{cpp -dM} to see them all. @xref{Invocation}. All system-specific
-predefined macros expand to the constant 1, so you can test them with
+predefined macros expand to a constant value, so you can test them with
either @samp{#ifdef} or @samp{#if}.
The C standard requires that all system-specific macros be part of the
@item
Macros can be defined or undefined with the @option{-D} and @option{-U}
-command line options when you compile the program. You can arrange to
+command-line options when you compile the program. You can arrange to
compile the same source file into two different programs by choosing a
macro name to specify which program you want, writing conditionals to
test whether or how this macro is defined, and then controlling the
-state of the macro with command line options, perhaps set in the
+state of the macro with command-line options, perhaps set in the
Makefile. @xref{Invocation}.
@item
an inconsistency and report it with @samp{#error}. For example,
@smallexample
-#if !defined(UNALIGNED_INT_ASM_OP) && defined(DWARF2_DEBUGGING_INFO)
-#error "DWARF2_DEBUGGING_INFO requires UNALIGNED_INT_ASM_OP."
+#if !defined(FOO) && defined(BAR)
+#error "BAR requires FOO."
#endif
@end smallexample
current file to be treated as if it came from a system header.
@xref{System Headers}.
+@item #pragma GCC warning
+@itemx #pragma GCC error
+@code{#pragma GCC warning "message"} causes the preprocessor to issue
+a warning diagnostic with the text @samp{message}. The message
+contained in the pragma must be a single string literal. Similarly,
+@code{#pragma GCC error "message"} issues an error message. Unlike
+the @samp{#warning} and @samp{#error} directives, these pragmas can be
+embedded in preprocessor macros using @samp{_Pragma}.
+
@end ftable
@node Other Directives
Normally comments are removed from the replacement text after the
macro is expanded, but if the @option{-CC} option is passed on the
-command line comments are preserved. (In fact, the current
+command-line comments are preserved. (In fact, the current
implementation removes comments even before saving the macro
replacement text, but it careful to do it in such a way that the
observed effect is identical even in the function-like macro case.)
The C and C++ standards allow identifiers to be composed of @samp{_}
and the alphanumeric characters. C++ and C99 also allow universal
character names, and C99 further permits implementation-defined
-characters. GCC currently only permits universal character names if
-@option{-fextended-identifiers} is used, because the implementation of
-universal character names in identifiers is experimental.
+characters.
GCC allows the @samp{$} character in identifiers as an extension for
most targets. This is true regardless of the @option{std=} switch,
In either form, if no such assertion has been made, @samp{#unassert} has
no effect.
-You can also make or cancel assertions using command line options.
+You can also make or cancel assertions using command-line options.
@xref{Invocation}.
@node Differences from previous versions
@emph{Note:} Whether you use the preprocessor by way of @command{gcc}
or @command{cpp}, the @dfn{compiler driver} is run first. This
program's purpose is to translate your command into invocations of the
-programs that do the actual work. Their command line interfaces are
+programs that do the actual work. Their command-line interfaces are
similar but not identical to the documented interface, and may change
without notice.
@node Option Index
@unnumbered Option Index
@noindent
-CPP's command line options and environment variables are indexed here
+CPP's command-line options and environment variables are indexed here
without any initial @samp{-} or @samp{--}.
@printindex op
projects / thirdparty / gcc.git / blobdiff