@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
+2008, 2009, 2010, 2011
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 1.2 or
+under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation. A copy of
the license is included in the
@c man end
few things required by the standard. These are features which are
rarely, if ever, used, and may cause surprising changes to the meaning
of a program which does not expect them. To get strict ISO Standard C,
-you should use the @option{-std=c90} or @option{-std=c99} options, depending
+you should use the @option{-std=c90}, @option{-std=c99} or
+@option{-std=c1x} options, depending
on which version of the standard you want. To get all the mandatory
diagnostics, you must also use @option{-pedantic}. @xref{Invocation}.
which use it. Otherwise, the precompiled headers will not be used.
@item __GFORTRAN__
-The GNU Fortran compiler defines this.
+The GNU Fortran compiler defines this.
@item __GNUC__
@itemx __GNUC_MINOR__
@code{double}, @code{long double}, @code{size_t}, @code{wchar_t}, @code{wint_t}
and @code{ptrdiff_t}.
+@item __BYTE_ORDER__
+@itemx __ORDER_LITTLE_ENDIAN__
+@itemx __ORDER_BIG_ENDIAN__
+@itemx __ORDER_PDP_ENDIAN__
+@code{__BYTE_ORDER__} is defined to one of the values
+@code{__ORDER_LITTLE_ENDIAN__}, @code{__ORDER_BIG_ENDIAN__}, or
+@code{__ORDER_PDP_ENDIAN__} to reflect the layout of multi-byte and
+multi-word quantities in memory. If @code{__BYTE_ORDER__} is equal to
+@code{__ORDER_LITTLE_ENDIAN__} or @code{__ORDER_BIG_ENDIAN__}, then
+multi-byte and multi-word quantities are laid out identically: the
+byte (word) at the lowest address is the least significant or most
+significant byte (word) of the quantity, respectively. If
+@code{__BYTE_ORDER__} is equal to @code{__ORDER_PDP_ENDIAN__}, then
+bytes in 16-bit words are laid out in a little-endian fashion, whereas
+the 16-bit subwords of a 32-bit quantity are laid out in big-endian
+fashion.
+
+You should use these macros for testing like this:
+
+@smallexample
+/* @r{Test for a little-endian machine} */
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+@end smallexample
+
+@item __FLOAT_WORD_ORDER__
+@code{__FLOAT_WORD_ORDER__} is defined to one of the values
+@code{__ORDER_LITTLE_ENDIAN__} or @code{__ORDER_BIG_ENDIAN__} to reflect
+the layout of the words of multi-word floating-point quantities.
+
@item __DEPRECATED
This macro is defined, with value 1, when compiling a C++ source file
with warnings about deprecated constructs enabled. These warnings are
This macro is defined when the compiler is emitting Dwarf2 CFI directives
to the assembler. When this is defined, it is possible to emit those same
directives in inline assembly.
+
+@item __FP_FAST_FMA
+@itemx __FP_FAST_FMAF
+@itemx __FP_FAST_FMAL
+These macros are defined with value 1 if the backend supports the
+@code{fma}, @code{fmaf}, and @code{fmal} builtin functions, so that
+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.
@end table
@node System-specific Predefined Macros
@subsection C++ Named Operators
@cindex named operators
@cindex C++ named operators
-@cindex iso646.h
+@cindex @file{iso646.h}
In C++, there are eleven keywords which are simply alternate spellings
of operators normally written with punctuation. These keywords are
define them with preprocessing directives or command-line options.
Assertions were intended to provide a more systematic way to describe
-the compiler's target system. However, in practice they are just as
-unpredictable as the system-specific predefined macros. In addition, they
-are not part of any standard, and only a few compilers support them.
+the compiler's target system and we added them for compatibility with
+existing compilers. In practice they are just as unpredictable as the
+system-specific predefined macros. In addition, they are not part of
+any standard, and only a few compilers support them.
Therefore, the use of assertions is @strong{less} portable than the use
of system-specific predefined macros. We recommend you do not use them at
all.
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