-@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1996, 1998, 1999, 2000,
-@c 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1996, 1998, 1999, 2000, 2001,
+@c 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
* Conditionals:: Omitting the middle operand of a @samp{?:} expression.
* Long Long:: Double-word integers---@code{long long int}.
* Complex:: Data types for complex numbers.
+* Floating Types:: Additional Floating Types.
* Decimal Float:: Decimal Floating Types.
* Hex Floats:: Hexadecimal floating-point constants.
+* Fixed-Point:: Fixed-Point Types.
* Zero Length:: Zero-length arrays.
* Variable Length:: Arrays whose length is computed at run time.
* Empty Structures:: Structures with no members.
* Pragmas:: Pragmas accepted by GCC.
* Unnamed Fields:: Unnamed struct/union fields within structs/unions.
* Thread-Local:: Per-thread variables.
+* Binary constants:: Binary constants using the @samp{0b} prefix.
@end menu
@node Statement Exprs
the number of dynamic relocations that are needed, and by consequence,
allows the data to be read-only.
+The @code{&&foo} expressions for the same label might have different values
+if the containing function is inlined or cloned. If a program relies on
+them being always the same, @code{__attribute__((__noinline__))} should
+be used to prevent inlining. If @code{&&foo} is used
+in a static variable initializer, inlining is forbidden.
+
@node Nested Functions
@section Nested Functions
@cindex nested functions
returned by @code{__builtin_apply}.
@end deftypefn
+@deftypefn {Built-in Function} __builtin_va_arg_pack ()
+This built-in function represents all anonymous arguments of an inline
+function. It can be used only in inline functions which will be always
+inlined, never compiled as a separate function, such as those using
+@code{__attribute__ ((__always_inline__))} or
+@code{__attribute__ ((__gnu_inline__))} extern inline functions.
+It must be only passed as last argument to some other function
+with variable arguments. This is useful for writing small wrapper
+inlines for variable argument functions, when using preprocessor
+macros is undesirable. For example:
+@smallexample
+extern int myprintf (FILE *f, const char *format, ...);
+extern inline __attribute__ ((__gnu_inline__)) int
+myprintf (FILE *f, const char *format, ...)
+@{
+ int r = fprintf (f, "myprintf: ");
+ if (r < 0)
+ return r;
+ int s = fprintf (f, format, __builtin_va_arg_pack ());
+ if (s < 0)
+ return s;
+ return r + s;
+@}
+@end smallexample
+@end deftypefn
+
+@deftypefn {Built-in Function} __builtin_va_arg_pack_len ()
+This built-in function returns the number of anonymous arguments of
+an inline function. It can be used only in inline functions which
+will be always inlined, never compiled as a separate function, such
+as those using @code{__attribute__ ((__always_inline__))} or
+@code{__attribute__ ((__gnu_inline__))} extern inline functions.
+For example following will do link or runtime checking of open
+arguments for optimized code:
+@smallexample
+#ifdef __OPTIMIZE__
+extern inline __attribute__((__gnu_inline__)) int
+myopen (const char *path, int oflag, ...)
+@{
+ if (__builtin_va_arg_pack_len () > 1)
+ warn_open_too_many_arguments ();
+
+ if (__builtin_constant_p (oflag))
+ @{
+ if ((oflag & O_CREAT) != 0 && __builtin_va_arg_pack_len () < 1)
+ @{
+ warn_open_missing_mode ();
+ return __open_2 (path, oflag);
+ @}
+ return open (path, oflag, __builtin_va_arg_pack ());
+ @}
+
+ if (__builtin_va_arg_pack_len () < 1)
+ return __open_2 (path, oflag);
+
+ return open (path, oflag, __builtin_va_arg_pack ());
+@}
+#endif
+@end smallexample
+@end deftypefn
+
@node Typeof
@section Referring to a Type with @code{typeof}
@findex typeof
variables are named @code{foo$real} and @code{foo$imag}. You can
examine and set these two fictitious variables with your debugger.
+@node Floating Types
+@section Additional Floating Types
+@cindex additional floating types
+@cindex @code{__float80} data type
+@cindex @code{__float128} data type
+@cindex @code{w} floating point suffix
+@cindex @code{q} floating point suffix
+@cindex @code{W} floating point suffix
+@cindex @code{Q} floating point suffix
+
+As an extension, the GNU C compiler supports additional floating
+types, @code{__float80} and @code{__float128} to support 80bit
+(@code{XFmode}) and 128 bit (@code{TFmode}) floating types.
+Support for additional types includes the arithmetic operators:
+add, subtract, multiply, divide; unary arithmetic operators;
+relational operators; equality operators; and conversions to and from
+integer and other floating types. Use a suffix @samp{w} or @samp{W}
+in a literal constant of type @code{__float80} and @samp{q} or @samp{Q}
+for @code{_float128}. You can declare complex types using the
+corresponding internal complex type, @code{XCmode} for @code{__float80}
+type and @code{TCmode} for @code{__float128} type:
+
+@smallexample
+typedef _Complex float __attribute__((mode(TC))) _Complex128;
+typedef _Complex float __attribute__((mode(XC))) _Complex80;
+@end smallexample
+
+Not all targets support additional floating point types. @code{__float80}
+is supported on i386, x86_64 and ia64 targets and target @code{__float128}
+is supported on x86_64 and ia64 targets.
+
@node Decimal Float
@section Decimal Floating Types
@cindex decimal floating types
could mean @code{1.0f} or @code{1.9375} since @samp{f} is also the
extension for floating-point constants of type @code{float}.
+@node Fixed-Point
+@section Fixed-Point Types
+@cindex fixed-point types
+@cindex @code{_Fract} data type
+@cindex @code{_Accum} data type
+@cindex @code{_Sat} data type
+@cindex @code{hr} fixed-suffix
+@cindex @code{r} fixed-suffix
+@cindex @code{lr} fixed-suffix
+@cindex @code{llr} fixed-suffix
+@cindex @code{uhr} fixed-suffix
+@cindex @code{ur} fixed-suffix
+@cindex @code{ulr} fixed-suffix
+@cindex @code{ullr} fixed-suffix
+@cindex @code{hk} fixed-suffix
+@cindex @code{k} fixed-suffix
+@cindex @code{lk} fixed-suffix
+@cindex @code{llk} fixed-suffix
+@cindex @code{uhk} fixed-suffix
+@cindex @code{uk} fixed-suffix
+@cindex @code{ulk} fixed-suffix
+@cindex @code{ullk} fixed-suffix
+@cindex @code{HR} fixed-suffix
+@cindex @code{R} fixed-suffix
+@cindex @code{LR} fixed-suffix
+@cindex @code{LLR} fixed-suffix
+@cindex @code{UHR} fixed-suffix
+@cindex @code{UR} fixed-suffix
+@cindex @code{ULR} fixed-suffix
+@cindex @code{ULLR} fixed-suffix
+@cindex @code{HK} fixed-suffix
+@cindex @code{K} fixed-suffix
+@cindex @code{LK} fixed-suffix
+@cindex @code{LLK} fixed-suffix
+@cindex @code{UHK} fixed-suffix
+@cindex @code{UK} fixed-suffix
+@cindex @code{ULK} fixed-suffix
+@cindex @code{ULLK} fixed-suffix
+
+As an extension, the GNU C compiler supports fixed-point types as
+defined in the N1169 draft of ISO/IEC DTR 18037. Support for fixed-point
+types in GCC will evolve as the draft technical report changes.
+Calling conventions for any target might also change. Not all targets
+support fixed-point types.
+
+The fixed-point types are
+@code{short _Fract},
+@code{_Fract},
+@code{long _Fract},
+@code{long long _Fract},
+@code{unsigned short _Fract},
+@code{unsigned _Fract},
+@code{unsigned long _Fract},
+@code{unsigned long long _Fract},
+@code{_Sat short _Fract},
+@code{_Sat _Fract},
+@code{_Sat long _Fract},
+@code{_Sat long long _Fract},
+@code{_Sat unsigned short _Fract},
+@code{_Sat unsigned _Fract},
+@code{_Sat unsigned long _Fract},
+@code{_Sat unsigned long long _Fract},
+@code{short _Accum},
+@code{_Accum},
+@code{long _Accum},
+@code{long long _Accum},
+@code{unsigned short _Accum},
+@code{unsigned _Accum},
+@code{unsigned long _Accum},
+@code{unsigned long long _Accum},
+@code{_Sat short _Accum},
+@code{_Sat _Accum},
+@code{_Sat long _Accum},
+@code{_Sat long long _Accum},
+@code{_Sat unsigned short _Accum},
+@code{_Sat unsigned _Accum},
+@code{_Sat unsigned long _Accum},
+@code{_Sat unsigned long long _Accum}.
+Fixed-point data values contain fractional and optional integral parts.
+The format of fixed-point data varies and depends on the target machine.
+
+Support for fixed-point types includes prefix and postfix increment
+and decrement operators (@code{++}, @code{--}); unary arithmetic operators
+(@code{+}, @code{-}, @code{!}); binary arithmetic operators (@code{+},
+@code{-}, @code{*}, @code{/}); binary shift operators (@code{<<}, @code{>>});
+relational operators (@code{<}, @code{<=}, @code{>=}, @code{>});
+equality operators (@code{==}, @code{!=}); assignment operators
+(@code{+=}, @code{-=}, @code{*=}, @code{/=}, @code{<<=}, @code{>>=});
+and conversions to and from integer, floating-point, or fixed-point types.
+
+Use a suffix @samp{hr} or @samp{HR} in a literal constant of type
+@code{short _Fract} and @code{_Sat short _Fract},
+@samp{r} or @samp{R} for @code{_Fract} and @code{_Sat _Fract},
+@samp{lr} or @samp{LR} for @code{long _Fract} and @code{_Sat long _Fract},
+@samp{llr} or @samp{LLR} for @code{long long _Fract} and
+@code{_Sat long long _Fract},
+@samp{uhr} or @samp{UHR} for @code{unsigned short _Fract} and
+@code{_Sat unsigned short _Fract},
+@samp{ur} or @samp{UR} for @code{unsigned _Fract} and
+@code{_Sat unsigned _Fract},
+@samp{ulr} or @samp{ULR} for @code{unsigned long _Fract} and
+@code{_Sat unsigned long _Fract},
+@samp{ullr} or @samp{ULLR} for @code{unsigned long long _Fract}
+and @code{_Sat unsigned long long _Fract},
+@samp{hk} or @samp{HK} for @code{short _Accum} and @code{_Sat short _Accum},
+@samp{k} or @samp{K} for @code{_Accum} and @code{_Sat _Accum},
+@samp{lk} or @samp{LK} for @code{long _Accum} and @code{_Sat long _Accum},
+@samp{llk} or @samp{LLK} for @code{long long _Accum} and
+@code{_Sat long long _Accum},
+@samp{uhk} or @samp{UHK} for @code{unsigned short _Accum} and
+@code{_Sat unsigned short _Accum},
+@samp{uk} or @samp{UK} for @code{unsigned _Accum} and
+@code{_Sat unsigned _Accum},
+@samp{ulk} or @samp{ULK} for @code{unsigned long _Accum} and
+@code{_Sat unsigned long _Accum},
+and @samp{ullk} or @samp{ULLK} for @code{unsigned long long _Accum}
+and @code{_Sat unsigned long long _Accum}.
+
+GCC support of fixed-point types as specified by the draft technical report
+is incomplete:
+
+@itemize @bullet
+@item
+Pragmas to control overflow and rounding behaviors are not implemented.
+@end itemize
+
+Fixed-point types are supported by the DWARF2 debug information format.
+
@node Zero Length
@section Arrays of Length Zero
@cindex arrays of length zero
attributes when making a declaration. This keyword is followed by an
attribute specification inside double parentheses. The following
attributes are currently defined for functions on all targets:
-@code{noreturn}, @code{returns_twice}, @code{noinline}, @code{always_inline},
-@code{flatten}, @code{pure}, @code{const}, @code{nothrow}, @code{sentinel},
-@code{format}, @code{format_arg}, @code{no_instrument_function},
-@code{section}, @code{constructor}, @code{destructor}, @code{used},
-@code{unused}, @code{deprecated}, @code{weak}, @code{malloc},
-@code{alias}, @code{warn_unused_result}, @code{nonnull},
-@code{gnu_inline} and @code{externally_visible}, @code{hot}, @code{cold}.
-Several other attributes are defined for functions on particular target
-systems. Other attributes, including @code{section} are supported for
-variables declarations (@pxref{Variable Attributes}) and for types (@pxref{Type
-Attributes}).
+@code{aligned}, @code{alloc_size}, @code{noreturn},
+@code{returns_twice}, @code{noinline}, @code{always_inline},
+@code{flatten}, @code{pure}, @code{const}, @code{nothrow},
+@code{sentinel}, @code{format}, @code{format_arg},
+@code{no_instrument_function}, @code{section}, @code{constructor},
+@code{destructor}, @code{used}, @code{unused}, @code{deprecated},
+@code{weak}, @code{malloc}, @code{alias}, @code{warn_unused_result},
+@code{nonnull}, @code{gnu_inline}, @code{externally_visible},
+@code{hot}, @code{cold}, @code{artificial}, @code{error}
+and @code{warning}.
+Several other attributes are defined for functions on particular
+target systems. Other attributes, including @code{section} are
+supported for variables declarations (@pxref{Variable Attributes}) and
+for types (@pxref{Type Attributes}).
You may also specify attributes with @samp{__} preceding and following
each keyword. This allows you to use them in header files without
Not all target machines support this attribute.
+@item aligned (@var{alignment})
+@cindex @code{aligned} attribute
+This attribute specifies a minimum alignment for the function,
+measured in bytes.
+
+You cannot use this attribute to decrease the alignment of a function,
+only to increase it. However, when you explicitly specify a function
+alignment this will override the effect of the
+@option{-falign-functions} (@pxref{Optimize Options}) option for this
+function.
+
+Note that the effectiveness of @code{aligned} attributes may be
+limited by inherent limitations in your linker. On many systems, the
+linker is only able to arrange for functions to be aligned up to a
+certain maximum alignment. (For some linkers, the maximum supported
+alignment may be very very small.) See your linker documentation for
+further information.
+
+The @code{aligned} attribute can also be used for variables and fields
+(@pxref{Variable Attributes}.)
+
+@item alloc_size
+@cindex @code{alloc_size} attribute
+The @code{alloc_size} attribute is used to tell the compiler that the
+function return value points to memory, where the size is given by
+one or two of the functions parameters. GCC uses this
+information to improve the correctness of @code{__builtin_object_size}.
+
+The function parameter(s) denoting the allocated size are specified by
+one or two integer arguments supplied to the attribute. The allocated size
+is either the value of the single function argument specified or the product
+of the two function arguments specified. Argument numbering starts at
+one.
+
+For instance,
+
+@smallexample
+void* my_calloc(size_t, size_t) __attribute__((alloc_size(1,2)))
+void my_realloc(void* size_t) __attribute__((alloc_size(2)))
+@end smallexample
+
+declares that my_calloc will return memory of the size given by
+the product of parameter 1 and 2 and that my_realloc will return memory
+of the size given by parameter 2.
+
@item always_inline
@cindex @code{always_inline} function attribute
Generally, functions are not inlined unless optimization is specified.
definitions of the functions need not be precisely the same, although
if they do not have the same effect your program may behave oddly.
-If the function is neither @code{extern} nor @code{static}, then the
-function is compiled as a standalone function, as well as being
+In C, if the function is neither @code{extern} nor @code{static}, then
+the function is compiled as a standalone function, as well as being
inlined where possible.
This is how GCC traditionally handled functions declared
@code{__GNUC_STDC_INLINE__} are defined. @xref{Inline,,An Inline
Function is As Fast As a Macro}.
+In C++, this attribute does not depend on @code{extern} in any way,
+but it still requires the @code{inline} keyword to enable its special
+behavior.
+
+@cindex @code{artificial} function attribute
+@item artificial
+This attribute is useful for small inline wrappers which if possible
+should appear during debugging as a unit, depending on the debug
+info format it will either mean marking the function as artificial
+or using the caller location for all instructions within the inlined
+body.
+
@cindex @code{flatten} function attribute
@item flatten
Generally, inlining into a function is limited. For a function marked with
the current inlining parameters. The @code{flatten} attribute only works
reliably in unit-at-a-time mode.
+@item error ("@var{message}")
+@cindex @code{error} function attribute
+If this attribute is used on a function declaration and a call to such a function
+is not eliminated through dead code elimination or other optimizations, an error
+which will include @var{message} will be diagnosed. This is useful
+for compile time checking, especially together with @code{__builtin_constant_p}
+and inline functions where checking the inline function arguments is not
+possible through @code{extern char [(condition) ? 1 : -1];} tricks.
+While it is possible to leave the function undefined and thus invoke
+a link failure, when using this attribute the problem will be diagnosed
+earlier and with exact location of the call even in presence of inline
+functions or when not emitting debugging information.
+
+@item warning ("@var{message}")
+@cindex @code{warning} function attribute
+If this attribute is used on a function declaration and a call to such a function
+is not eliminated through dead code elimination or other optimizations, a warning
+which will include @var{message} will be diagnosed. This is useful
+for compile time checking, especially together with @code{__builtin_constant_p}
+and inline functions. While it is possible to define the function with
+a message in @code{.gnu.warning*} section, when using this attribute the problem
+will be diagnosed earlier and with exact location of the call even in presence
+of inline functions or when not emitting debugging information.
+
@item cdecl
@cindex functions that do pop the argument stack on the 386
@opindex mrtd
compilers.
On systems that support the @code{visibility} attribute, this
-attribute also implies ``default'' visibility, unless a
-@code{visibility} attribute is explicitly specified. You should avoid
-the use of @code{dllexport} with ``hidden'' or ``internal''
-visibility; in the future GCC may issue an error for those cases.
+attribute also implies ``default'' visibility. It is an error to
+explicitly specify any other visibility.
Currently, the @code{dllexport} attribute is ignored for inlined
functions, unless the @option{-fkeep-inline-functions} flag has been
On Microsoft Windows and Symbian OS targets, the @code{dllimport}
attribute causes the compiler to reference a function or variable via
a global pointer to a pointer that is set up by the DLL exporting the
-symbol. The attribute implies @code{extern} storage. On Microsoft
-Windows targets, the pointer name is formed by combining @code{_imp__}
-and the function or variable name.
+symbol. The attribute implies @code{extern}. On Microsoft Windows
+targets, the pointer name is formed by combining @code{_imp__} and the
+function or variable name.
You can use @code{__declspec(dllimport)} as a synonym for
@code{__attribute__ ((dllimport))} for compatibility with other
compilers.
+On systems that support the @code{visibility} attribute, this
+attribute also implies ``default'' visibility. It is an error to
+explicitly specify any other visibility.
+
Currently, the attribute is ignored for inlined functions. If the
attribute is applied to a symbol @emph{definition}, an error is reported.
If a symbol previously declared @code{dllimport} is later defined, the
functions, using the attribute for a variable eliminates a thunk in
the DLL@.
-One drawback to using this attribute is that a pointer to a function
-or variable marked as @code{dllimport} cannot be used as a constant
-address. On Microsoft Windows targets, the attribute can be disabled
+One drawback to using this attribute is that a pointer to a
+@emph{variable} marked as @code{dllimport} cannot be used as a constant
+address. However, a pointer to a @emph{function} with the
+@code{dllimport} attribute can be used as a constant initializer; in
+this case, the address of a stub function in the import lib is
+referenced. On Microsoft Windows targets, the attribute can be disabled
for functions by setting the @option{-mnop-fun-dllimport} flag.
@item eightbit_data
Controlling C Dialect}.
@item function_vector
-@cindex calling functions through the function vector on the H8/300 processors
+@cindex calling functions through the function vector on H8/300, M16C, and M32C processors
Use this attribute on the H8/300, H8/300H, and H8S to indicate that the specified
function should be called through the function vector. Calling a
function through the function vector will reduce code size, however;
You must use GAS and GLD from GNU binutils version 2.7 or later for
this attribute to work correctly.
+On M16C/M32C targets, the @code{function_vector} attribute declares a
+special page subroutine call function. Use of this attribute reduces
+the code size by 2 bytes for each call generated to the
+subroutine. The argument to the attribute is the vector number entry
+from the special page vector table which contains the 16 low-order
+bits of the subroutine's entry address. Each vector table has special
+page number (18 to 255) which are used in @code{jsrs} instruction.
+Jump addresses of the routines are generated by adding 0x0F0000 (in
+case of M16C targets) or 0xFF0000 (in case of M32C targets), to the 2
+byte addresses set in the vector table. Therefore you need to ensure
+that all the special page vector routines should get mapped within the
+address range 0x0F0000 to 0x0FFFFF (for M16C) and 0xFF0000 to 0xFFFFFF
+(for M32C).
+
+In the following example 2 bytes will be saved for each call to
+function @code{foo}.
+
+@smallexample
+void foo (void) __attribute__((function_vector(0x18)));
+void foo (void)
+@{
+@}
+
+void bar (void)
+@{
+ foo();
+@}
+@end smallexample
+
+If functions are defined in one file and are called in another file,
+then be sure to write this declaration in both files.
+
+This attribute is ignored for R8C target.
+
@item interrupt
@cindex interrupt handler functions
-Use this attribute on the ARM, AVR, C4x, CRX, M32C, M32R/D, MS1, and Xstormy16
-ports to indicate that the specified function is an interrupt handler.
-The compiler will generate function entry and exit sequences suitable
-for use in an interrupt handler when this attribute is present.
+Use this attribute on the ARM, AVR, CRX, M32C, M32R/D, m68k, MS1,
+and Xstormy16 ports to indicate that the specified function is an
+interrupt handler. The compiler will generate function entry and exit
+sequences suitable for use in an interrupt handler when this attribute
+is present.
-Note, interrupt handlers for the Blackfin, m68k, H8/300, H8/300H, H8S, and
+Note, interrupt handlers for the Blackfin, H8/300, H8/300H, H8S, and
SH processors can be specified via the @code{interrupt_handler} attribute.
Note, on the AVR, interrupts will be enabled inside the function.
will generate function entry and exit sequences suitable for use in an
interrupt handler when this attribute is present.
+@item interrupt_thread
+@cindex interrupt thread functions on fido
+Use this attribute on fido, a subarchitecture of the m68k, to indicate
+that the specified function is an interrupt handler that is designed
+to run as a thread. The compiler omits generate prologue/epilogue
+sequences and replaces the return instruction with a @code{sleep}
+instruction. This attribute is available only on fido.
+
@item kspisusp
@cindex User stack pointer in interrupts on the Blackfin
When used together with @code{interrupt_handler}, @code{exception_handler}
or @code{nmi_handler}, code will be generated to load the stack pointer
from the USP register in the function prologue.
+@item l1_text
+@cindex @code{l1_text} function attribute
+This attribute specifies a function to be placed into L1 Instruction
+SRAM@. The function will be put into a specific section named @code{.l1.text}.
+With @option{-mfdpic}, function calls with a such function as the callee
+or caller will use inlined PLT.
+
@item long_call/short_call
@cindex indirect calls on ARM
This attribute specifies how a particular function is called on
@xref{RS/6000 and PowerPC Options}, for more information on whether long
calls are necessary.
-@item long_call
+@item long_call/near/far
@cindex indirect calls on MIPS
-This attribute specifies how a particular function is called on MIPS@.
-The attribute overrides the @option{-mlong-calls} (@pxref{MIPS Options})
-command line switch. This attribute causes the compiler to always call
+These attributes specify how a particular function is called on MIPS@.
+The attributes override the @option{-mlong-calls} (@pxref{MIPS Options})
+command-line switch. The @code{long_call} and @code{far} attributes are
+synonyms, and cause the compiler to always call
the function by first loading its address into a register, and then using
-the contents of that register.
+the contents of that register. The @code{near} attribute has the opposite
+effect; it specifies that non-PIC calls should be made using the more
+efficient @code{jal} instruction.
@item malloc
@cindex @code{malloc} attribute
to the new pointer) after the function returns a non-@code{NULL}
value.
+@item mips16/nomips16
+@cindex @code{mips16} attribute
+@cindex @code{nomips16} attribute
+
+On MIPS targets, you can use the @code{mips16} and @code{nomips16}
+function attributes to locally select or turn off MIPS16 code generation.
+A function with the @code{mips16} attribute is emitted as MIPS16 code,
+while MIPS16 code generation is disabled for functions with the
+@code{nomips16} attribute. These attributes override the
+@option{-mips16} and @option{-mno-mips16} options on the command line
+(@pxref{MIPS Options}).
+
+When compiling files containing mixed MIPS16 and non-MIPS16 code, the
+preprocessor symbol @code{__mips16} reflects the setting on the command line,
+not that within individual functions. Mixed MIPS16 and non-MIPS16 code
+may interact badly with some GCC extensions such as @code{__builtin_apply}
+(@pxref{Constructing Calls}).
+
@item model (@var{model-name})
@cindex function addressability on the M32R/D
@cindex variable addressability on the IA-64
@item naked
@cindex function without a prologue/epilogue code
-Use this attribute on the ARM, AVR, C4x, IP2K and SPU ports to indicate that
+Use this attribute on the ARM, AVR, IP2K and SPU ports to indicate that
the specified function does not need prologue/epilogue sequences generated by
the compiler. It is up to the programmer to provide these sequences.
@cindex @code{noinline} function attribute
This function attribute prevents a function from being considered for
inlining.
+@c Don't enumerate the optimizations by name here; we try to be
+@c future-compatible with this mechanism.
+If the function does not have side-effects, there are optimizations
+other than inlining that causes function calls to be optimized away,
+although the function call is live. To keep such calls from being
+optimized away, put
+@smallexample
+asm ("");
+@end smallexample
+(@pxref{Extended Asm}) in the called function, to serve as a special
+side-effect.
@item nonnull (@var{arg-index}, @dots{})
@cindex @code{nonnull} function attribute
many targets it is placed into special subsection of the text section so all
cold functions appears close together improving code locality of non-cold parts
of program. The paths leading to call of cold functions within code are marked
-as unlikely by the branch prediction mechanizm. It is thus useful to mark
+as unlikely by the branch prediction mechanism. It is thus useful to mark
functions used to handle unlikely conditions, such as @code{perror}, as cold to
improve optimization of hot functions that do call marked functions in rare
occasions.
An attribute specifier list may appear immediately before the comma,
@code{=} or semicolon terminating the declaration of an identifier other
-than a function definition. At present, such attribute specifiers apply
-to the declared object or function, but in future they may attach to the
-outermost adjacent declarator. In simple cases there is no difference,
-but, for example, in
-
-@smallexample
-void (****f)(void) __attribute__((noreturn));
-@end smallexample
-
-@noindent
-at present the @code{noreturn} attribute applies to @code{f}, which
-causes a warning since @code{f} is not a function, but in future it may
-apply to the function @code{****f}. The precise semantics of what
-attributes in such cases will apply to are not yet specified. Where an
+than a function definition. Such attribute specifiers apply
+to the declared object or function. Where an
assembler name for an object or function is specified (@pxref{Asm
-Labels}), at present the attribute must follow the @code{asm}
-specification; in future, attributes before the @code{asm} specification
-may apply to the adjacent declarator, and those after it to the declared
-object or function.
+Labels}), the attribute must follow the @code{asm}
+specification.
An attribute specifier list may, in future, be permitted to appear after
the declarator in a function definition (before any old-style parameter
instructions copy the biggest chunks of memory when performing copies to
or from the variables or fields that you have aligned this way.
-The @code{aligned} attribute can only increase the alignment; but you
-can decrease it by specifying @code{packed} as well. See below.
+When used on a struct, or struct member, the @code{aligned} attribute can
+only increase the alignment; in order to decrease it, the @code{packed}
+attribute must be specified as well. When used as part of a typedef, the
+@code{aligned} attribute can both increase and decrease alignment, and
+specifying the @code{packed} attribute will generate a warning.
Note that the effectiveness of @code{aligned} attributes may be limited
by inherent limitations in your linker. On many systems, the linker is
in an @code{__attribute__} will still only provide you with 8 byte
alignment. See your linker documentation for further information.
+The @code{aligned} attribute can also be used for functions
+(@pxref{Function Attributes}.)
+
@item cleanup (@var{cleanup_function})
@cindex @code{cleanup} attribute
The @code{cleanup} attribute runs a function when the variable goes
@end table
+@subsection Blackfin Variable Attributes
+
+Three attributes are currently defined for the Blackfin.
+
+@table @code
+@item l1_data
+@item l1_data_A
+@item l1_data_B
+@cindex @code{l1_data} variable attribute
+@cindex @code{l1_data_A} variable attribute
+@cindex @code{l1_data_B} variable attribute
+Use these attributes on the Blackfin to place the variable into L1 Data SRAM.
+Variables with @code{l1_data} attribute will be put into the specific section
+named @code{.l1.data}. Those with @code{l1_data_A} attribute will be put into
+the specific section named @code{.l1.data.A}. Those with @code{l1_data_B}
+attribute will be put into the specific section named @code{.l1.data.B}.
+@end table
+
@subsection M32R/D Variable Attributes
One attribute is currently defined for the M32R/D@.
@end table
+@subsection AVR Variable Attributes
+
+@table @code
+@item progmem
+@cindex @code{progmem} variable attribute
+The @code{progmem} attribute is used on the AVR to place data in the Program
+Memory address space. The AVR is a Harvard Architecture processor and data
+normally resides in the Data Memory address space.
+@end table
+
@node Type Attributes
@section Specifying Attributes of Types
@cindex attribute of types
macro of the same name. For example, you may use @code{__aligned__}
instead of @code{aligned}.
-You may specify type attributes either in a @code{typedef} declaration
-or in an enum, struct or union type declaration or definition.
+You may specify type attributes in an enum, struct or union type
+declaration or definition, or for other types in a @code{typedef}
+declaration.
For an enum, struct or union type, you may specify attributes either
between the enum, struct or union tag and the name of the type, or
as follows:
@smallexample
-typedef union
+typedef union __attribute__ ((__transparent_union__))
@{
int *__ip;
union wait *__up;
- @} wait_status_ptr_t __attribute__ ((__transparent_union__));
+ @} wait_status_ptr_t;
pid_t wait (wait_status_ptr_t);
@end smallexample
@end deftypefn
There are built-in functions added for many common string operation
-functions, e.g. for @code{memcpy} @code{__builtin___memcpy_chk}
+functions, e.g., for @code{memcpy} @code{__builtin___memcpy_chk}
built-in is provided. This built-in has an additional last argument,
which is the number of bytes remaining in object the @var{dest}
argument points to or @code{(size_t) -1} if the size is not known.
@end smallexample
The added @var{flag} argument is passed unchanged to @code{__sprintf_chk}
-etc. functions and can contain implementation specific flags on what
+etc.@: functions and can contain implementation specific flags on what
additional security measures the checking function might take, such as
handling @code{%n} differently.
@code{__builtin___fprintf_chk} and @code{__builtin___vfprintf_chk}.
These have just one additional argument, @var{flag}, right before
format string @var{fmt}. If the compiler is able to optimize them to
-@code{fputc} etc. functions, it will, otherwise the checking function
+@code{fputc} etc.@: functions, it will, otherwise the checking function
should be called and the @var{flag} argument passed to it.
@node Other Builtins
@section Other built-in functions provided by GCC
@cindex built-in functions
+@findex __builtin_isfinite
+@findex __builtin_isnormal
@findex __builtin_isgreater
@findex __builtin_isgreaterequal
@findex __builtin_isless
@findex gamma
@findex gammaf
@findex gammal
+@findex gamma_r
+@findex gammaf_r
+@findex gammal_r
@findex gettext
@findex hypot
@findex hypotf
@findex lgamma
@findex lgammaf
@findex lgammal
+@findex lgamma_r
+@findex lgammaf_r
+@findex lgammal_r
@findex llabs
@findex llrint
@findex llrintf
@findex lroundf
@findex lroundl
@findex malloc
+@findex memchr
@findex memcmp
@findex memcpy
@findex mempcpy
@findex signbit
@findex signbitf
@findex signbitl
+@findex signbitd32
+@findex signbitd64
+@findex signbitd128
@findex significand
@findex significandf
@findex significandl
@code{_exit}, @code{alloca}, @code{bcmp}, @code{bzero},
@code{dcgettext}, @code{dgettext}, @code{dremf}, @code{dreml},
@code{drem}, @code{exp10f}, @code{exp10l}, @code{exp10}, @code{ffsll},
-@code{ffsl}, @code{ffs}, @code{fprintf_unlocked}, @code{fputs_unlocked},
-@code{gammaf}, @code{gammal}, @code{gamma}, @code{gettext},
+@code{ffsl}, @code{ffs}, @code{fprintf_unlocked},
+@code{fputs_unlocked}, @code{gammaf}, @code{gammal}, @code{gamma},
+@code{gammaf_r}, @code{gammal_r}, @code{gamma_r}, @code{gettext},
@code{index}, @code{isascii}, @code{j0f}, @code{j0l}, @code{j0},
@code{j1f}, @code{j1l}, @code{j1}, @code{jnf}, @code{jnl}, @code{jn},
-@code{mempcpy}, @code{pow10f}, @code{pow10l}, @code{pow10},
-@code{printf_unlocked}, @code{rindex}, @code{scalbf}, @code{scalbl},
-@code{scalb}, @code{signbit}, @code{signbitf}, @code{signbitl},
-@code{significandf}, @code{significandl}, @code{significand},
-@code{sincosf}, @code{sincosl}, @code{sincos}, @code{stpcpy},
-@code{stpncpy}, @code{strcasecmp}, @code{strdup}, @code{strfmon},
-@code{strncasecmp}, @code{strndup}, @code{toascii}, @code{y0f},
-@code{y0l}, @code{y0}, @code{y1f}, @code{y1l}, @code{y1}, @code{ynf},
-@code{ynl} and @code{yn}
+@code{lgammaf_r}, @code{lgammal_r}, @code{lgamma_r}, @code{mempcpy},
+@code{pow10f}, @code{pow10l}, @code{pow10}, @code{printf_unlocked},
+@code{rindex}, @code{scalbf}, @code{scalbl}, @code{scalb},
+@code{signbit}, @code{signbitf}, @code{signbitl}, @code{signbitd32},
+@code{signbitd64}, @code{signbitd128}, @code{significandf},
+@code{significandl}, @code{significand}, @code{sincosf},
+@code{sincosl}, @code{sincos}, @code{stpcpy}, @code{stpncpy},
+@code{strcasecmp}, @code{strdup}, @code{strfmon}, @code{strncasecmp},
+@code{strndup}, @code{toascii}, @code{y0f}, @code{y0l}, @code{y0},
+@code{y1f}, @code{y1l}, @code{y1}, @code{ynf}, @code{ynl} and
+@code{yn}
may be handled as built-in functions.
All these functions have corresponding versions
prefixed with @code{__builtin_}, which may be used even in strict C89
@code{isgraph}, @code{islower}, @code{isprint}, @code{ispunct},
@code{isspace}, @code{isupper}, @code{isxdigit}, @code{tolower},
@code{toupper}, @code{labs}, @code{ldexp}, @code{log10}, @code{log},
-@code{malloc}, @code{memcmp}, @code{memcpy}, @code{memset}, @code{modf},
-@code{pow}, @code{printf}, @code{putchar}, @code{puts}, @code{scanf},
-@code{sinh}, @code{sin}, @code{snprintf}, @code{sprintf}, @code{sqrt},
-@code{sscanf}, @code{strcat}, @code{strchr}, @code{strcmp},
-@code{strcpy}, @code{strcspn}, @code{strlen}, @code{strncat},
-@code{strncmp}, @code{strncpy}, @code{strpbrk}, @code{strrchr},
-@code{strspn}, @code{strstr}, @code{tanh}, @code{tan}, @code{vfprintf},
-@code{vprintf} and @code{vsprintf}
+@code{malloc}, @code{memchr}, @code{memcmp}, @code{memcpy},
+@code{memset}, @code{modf}, @code{pow}, @code{printf}, @code{putchar},
+@code{puts}, @code{scanf}, @code{sinh}, @code{sin}, @code{snprintf},
+@code{sprintf}, @code{sqrt}, @code{sscanf}, @code{strcat},
+@code{strchr}, @code{strcmp}, @code{strcpy}, @code{strcspn},
+@code{strlen}, @code{strncat}, @code{strncmp}, @code{strncpy},
+@code{strpbrk}, @code{strrchr}, @code{strspn}, @code{strstr},
+@code{tanh}, @code{tan}, @code{vfprintf}, @code{vprintf} and @code{vsprintf}
are all recognized as built-in functions unless
@option{-fno-builtin} is specified (or @option{-fno-builtin-@var{function}}
is specified for an individual function). All of these functions have
@code{islessgreater}, and @code{isunordered}) , with @code{__builtin_}
prefixed. We intend for a library implementor to be able to simply
@code{#define} each standard macro to its built-in equivalent.
+In the same fashion, GCC provides @code{isfinite} and @code{isnormal}
+built-ins used with @code{__builtin_} prefixed.
@deftypefn {Built-in Function} int __builtin_types_compatible_p (@var{type1}, @var{type2})
when testing pointer or floating-point values.
@end deftypefn
+@deftypefn {Built-in Function} void __builtin_trap (void)
+This function causes the program to exit abnormally. GCC implements
+this function by using a target-dependent mechanism (such as
+intentionally executing an illegal instruction) or by calling
+@code{abort}. The mechanism used may vary from release to release so
+you should not rely on any particular implementation.
+@end deftypefn
+
+@deftypefn {Built-in Function} void __builtin___clear_cache (char *@var{begin}, char *@var{end})
+This function is used to flush the processor's instruction cache for
+the region of memory between @var{begin} inclusive and @var{end}
+exclusive. Some targets require that the instruction cache be
+flushed, after modifying memory containing code, in order to obtain
+deterministic behavior.
+
+If the target does not require instruction cache flushes,
+@code{__builtin___clear_cache} has no effect. Otherwise either
+instructions are emitted in-line to clear the instruction cache or a
+call to the @code{__clear_cache} function in libgcc is made.
+@end deftypefn
+
@deftypefn {Built-in Function} void __builtin_prefetch (const void *@var{addr}, ...)
This function is used to minimize cache-miss latency by moving data into
a cache before it is accessed.
@menu
* Alpha Built-in Functions::
-* ARM Built-in Functions::
+* ARM iWMMXt Built-in Functions::
+* ARM NEON Intrinsics::
* Blackfin Built-in Functions::
* FR-V Built-in Functions::
* X86 Built-in Functions::
void __builtin_set_thread_pointer (void *)
@end smallexample
-@node ARM Built-in Functions
-@subsection ARM Built-in Functions
+@node ARM iWMMXt Built-in Functions
+@subsection ARM iWMMXt Built-in Functions
These built-in functions are available for the ARM family of
-processors, when the @option{-mcpu=iwmmxt} switch is used:
+processors when the @option{-mcpu=iwmmxt} switch is used:
@smallexample
typedef int v2si __attribute__ ((vector_size (8)));
long long __builtin_arm_wzero ()
@end smallexample
+@node ARM NEON Intrinsics
+@subsection ARM NEON Intrinsics
+
+These built-in intrinsics for the ARM Advanced SIMD extension are available
+when the @option{-mfpu=neon} switch is used:
+
+@include arm-neon-intrinsics.texi
+
@node Blackfin Built-in Functions
@subsection Blackfin Built-in Functions
entire vector register, interpreting it as a 128-bit integer, these use mode
@code{TI}.
+In 64-bit mode, the x86-64 family of processors uses additional built-in
+functions for efficient use of @code{TF} (@code{__float128}) 128-bit
+floating point and @code{TC} 128-bit complex floating point values.
+
+The following floating point built-in functions are available in 64-bit
+mode. All of them implement the function that is part of the name.
+
+@smallexample
+__float128 __builtin_fabsq (__float128)
+__float128 __builtin_copysignq (__float128, __float128)
+@end smallexample
+
+The following floating point built-in functions are made available in the
+64-bit mode.
+
+@table @code
+@item __float128 __builtin_infq (void)
+Similar to @code{__builtin_inf}, except the return type is @code{__float128}.
+@end table
+
The following built-in functions are made available by @option{-mmmx}.
All of them generate the machine instruction that is part of the name.
v8qi __builtin_ia32_packsswb (v4hi, v4hi)
v4hi __builtin_ia32_packssdw (v2si, v2si)
v8qi __builtin_ia32_packuswb (v4hi, v4hi)
+
+v4hi __builtin_ia32_psllw (v4hi, v4hi)
+v2si __builtin_ia32_pslld (v2si, v2si)
+v1di __builtin_ia32_psllq (v1di, v1di)
+v4hi __builtin_ia32_psrlw (v4hi, v4hi)
+v2si __builtin_ia32_psrld (v2si, v2si)
+v1di __builtin_ia32_psrlq (v1di, v1di)
+v4hi __builtin_ia32_psraw (v4hi, v4hi)
+v2si __builtin_ia32_psrad (v2si, v2si)
+v4hi __builtin_ia32_psllwi (v4hi, int)
+v2si __builtin_ia32_pslldi (v2si, int)
+v1di __builtin_ia32_psllqi (v1di, int)
+v4hi __builtin_ia32_psrlwi (v4hi, int)
+v2si __builtin_ia32_psrldi (v2si, int)
+v1di __builtin_ia32_psrlqi (v1di, int)
+v4hi __builtin_ia32_psrawi (v4hi, int)
+v2si __builtin_ia32_psradi (v2si, int)
+
@end smallexample
The following built-in functions are made available either with
void __builtin_ia32_storedqu (char *, v16qi)
unsigned long long __builtin_ia32_pmuludq (v2si, v2si)
v2di __builtin_ia32_pmuludq128 (v4si, v4si)
-v8hi __builtin_ia32_psllw128 (v8hi, v2di)
-v4si __builtin_ia32_pslld128 (v4si, v2di)
-v2di __builtin_ia32_psllq128 (v4si, v2di)
-v8hi __builtin_ia32_psrlw128 (v8hi, v2di)
-v4si __builtin_ia32_psrld128 (v4si, v2di)
+v8hi __builtin_ia32_psllw128 (v8hi, v8hi)
+v4si __builtin_ia32_pslld128 (v4si, v4si)
+v2di __builtin_ia32_psllq128 (v2di, v2di)
+v8hi __builtin_ia32_psrlw128 (v8hi, v8hi)
+v4si __builtin_ia32_psrld128 (v4si, v4si)
v2di __builtin_ia32_psrlq128 (v2di, v2di)
-v8hi __builtin_ia32_psraw128 (v8hi, v2di)
-v4si __builtin_ia32_psrad128 (v4si, v2di)
+v8hi __builtin_ia32_psraw128 (v8hi, v8hi)
+v4si __builtin_ia32_psrad128 (v4si, v4si)
v2di __builtin_ia32_pslldqi128 (v2di, int)
v8hi __builtin_ia32_psllwi128 (v8hi, int)
v4si __builtin_ia32_pslldi128 (v4si, int)
v8hi __builtin_ia32_pabsw128 (v8hi)
@end smallexample
+The following built-in functions are available when @option{-msse4.1} is
+used. All of them generate the machine instruction that is part of the
+name.
+
+@smallexample
+v2df __builtin_ia32_blendpd (v2df, v2df, const int)
+v4sf __builtin_ia32_blendps (v4sf, v4sf, const int)
+v2df __builtin_ia32_blendvpd (v2df, v2df, v2df)
+v4sf __builtin_ia32_blendvps (v4sf, v4sf, v4sf)
+v2df __builtin_ia32_dppd (v2df, v2df, const int)
+v4sf __builtin_ia32_dpps (v4sf, v4sf, const int)
+v4sf __builtin_ia32_insertps128 (v4sf, v4sf, const int)
+v2di __builtin_ia32_movntdqa (v2di *);
+v16qi __builtin_ia32_mpsadbw128 (v16qi, v16qi, const int)
+v8hi __builtin_ia32_packusdw128 (v4si, v4si)
+v16qi __builtin_ia32_pblendvb128 (v16qi, v16qi, v16qi)
+v8hi __builtin_ia32_pblendw128 (v8hi, v8hi, const int)
+v2di __builtin_ia32_pcmpeqq (v2di, v2di)
+v8hi __builtin_ia32_phminposuw128 (v8hi)
+v16qi __builtin_ia32_pmaxsb128 (v16qi, v16qi)
+v4si __builtin_ia32_pmaxsd128 (v4si, v4si)
+v4si __builtin_ia32_pmaxud128 (v4si, v4si)
+v8hi __builtin_ia32_pmaxuw128 (v8hi, v8hi)
+v16qi __builtin_ia32_pminsb128 (v16qi, v16qi)
+v4si __builtin_ia32_pminsd128 (v4si, v4si)
+v4si __builtin_ia32_pminud128 (v4si, v4si)
+v8hi __builtin_ia32_pminuw128 (v8hi, v8hi)
+v4si __builtin_ia32_pmovsxbd128 (v16qi)
+v2di __builtin_ia32_pmovsxbq128 (v16qi)
+v8hi __builtin_ia32_pmovsxbw128 (v16qi)
+v2di __builtin_ia32_pmovsxdq128 (v4si)
+v4si __builtin_ia32_pmovsxwd128 (v8hi)
+v2di __builtin_ia32_pmovsxwq128 (v8hi)
+v4si __builtin_ia32_pmovzxbd128 (v16qi)
+v2di __builtin_ia32_pmovzxbq128 (v16qi)
+v8hi __builtin_ia32_pmovzxbw128 (v16qi)
+v2di __builtin_ia32_pmovzxdq128 (v4si)
+v4si __builtin_ia32_pmovzxwd128 (v8hi)
+v2di __builtin_ia32_pmovzxwq128 (v8hi)
+v2di __builtin_ia32_pmuldq128 (v4si, v4si)
+v4si __builtin_ia32_pmulld128 (v4si, v4si)
+int __builtin_ia32_ptestc128 (v2di, v2di)
+int __builtin_ia32_ptestnzc128 (v2di, v2di)
+int __builtin_ia32_ptestz128 (v2di, v2di)
+v2df __builtin_ia32_roundpd (v2df, const int)
+v4sf __builtin_ia32_roundps (v4sf, const int)
+v2df __builtin_ia32_roundsd (v2df, v2df, const int)
+v4sf __builtin_ia32_roundss (v4sf, v4sf, const int)
+@end smallexample
+
+The following built-in functions are available when @option{-msse4.1} is
+used.
+
+@table @code
+@item v4sf __builtin_ia32_vec_set_v4sf (v4sf, float, const int)
+Generates the @code{insertps} machine instruction.
+@item int __builtin_ia32_vec_ext_v16qi (v16qi, const int)
+Generates the @code{pextrb} machine instruction.
+@item v16qi __builtin_ia32_vec_set_v16qi (v16qi, int, const int)
+Generates the @code{pinsrb} machine instruction.
+@item v4si __builtin_ia32_vec_set_v4si (v4si, int, const int)
+Generates the @code{pinsrd} machine instruction.
+@item v2di __builtin_ia32_vec_set_v2di (v2di, long long, const int)
+Generates the @code{pinsrq} machine instruction in 64bit mode.
+@end table
+
+The following built-in functions are changed to generate new SSE4.1
+instructions when @option{-msse4.1} is used.
+
+@table @code
+@item float __builtin_ia32_vec_ext_v4sf (v4sf, const int)
+Generates the @code{extractps} machine instruction.
+@item int __builtin_ia32_vec_ext_v4si (v4si, const int)
+Generates the @code{pextrd} machine instruction.
+@item long long __builtin_ia32_vec_ext_v2di (v2di, const int)
+Generates the @code{pextrq} machine instruction in 64bit mode.
+@end table
+
+The following built-in functions are available when @option{-msse4.2} is
+used. All of them generate the machine instruction that is part of the
+name.
+
+@smallexample
+v16qi __builtin_ia32_pcmpestrm128 (v16qi, int, v16qi, int, const int)
+int __builtin_ia32_pcmpestri128 (v16qi, int, v16qi, int, const int)
+int __builtin_ia32_pcmpestria128 (v16qi, int, v16qi, int, const int)
+int __builtin_ia32_pcmpestric128 (v16qi, int, v16qi, int, const int)
+int __builtin_ia32_pcmpestrio128 (v16qi, int, v16qi, int, const int)
+int __builtin_ia32_pcmpestris128 (v16qi, int, v16qi, int, const int)
+int __builtin_ia32_pcmpestriz128 (v16qi, int, v16qi, int, const int)
+v16qi __builtin_ia32_pcmpistrm128 (v16qi, v16qi, const int)
+int __builtin_ia32_pcmpistri128 (v16qi, v16qi, const int)
+int __builtin_ia32_pcmpistria128 (v16qi, v16qi, const int)
+int __builtin_ia32_pcmpistric128 (v16qi, v16qi, const int)
+int __builtin_ia32_pcmpistrio128 (v16qi, v16qi, const int)
+int __builtin_ia32_pcmpistris128 (v16qi, v16qi, const int)
+int __builtin_ia32_pcmpistriz128 (v16qi, v16qi, const int)
+v2di __builtin_ia32_pcmpgtq (v2di, v2di)
+@end smallexample
+
+The following built-in functions are available when @option{-msse4.2} is
+used.
+
+@table @code
+@item unsigned int __builtin_ia32_crc32qi (unsigned int, unsigned char)
+Generates the @code{crc32b} machine instruction.
+@item unsigned int __builtin_ia32_crc32hi (unsigned int, unsigned short)
+Generates the @code{crc32w} machine instruction.
+@item unsigned int __builtin_ia32_crc32si (unsigned int, unsigned int)
+Generates the @code{crc32l} machine instruction.
+@item unsigned long long __builtin_ia32_crc32di (unsigned int, unsigned long long)
+@end table
+
+The following built-in functions are changed to generate new SSE4.2
+instructions when @option{-msse4.2} is used.
+
+@table @code
+@item int __builtin_popcount (unsigned int)
+Generates the @code{popcntl} machine instruction.
+@item int __builtin_popcountl (unsigned long)
+Generates the @code{popcntl} or @code{popcntq} machine instruction,
+depending on the size of @code{unsigned long}.
+@item int __builtin_popcountll (unsigned long long)
+Generates the @code{popcntq} machine instruction.
+@end table
+
The following built-in functions are available when @option{-msse4a} is used.
+All of them generate the machine instruction that is part of the name.
+
+@smallexample
+void __builtin_ia32_movntsd (double *, v2df)
+void __builtin_ia32_movntss (float *, v4sf)
+v2di __builtin_ia32_extrq (v2di, v16qi)
+v2di __builtin_ia32_extrqi (v2di, const unsigned int, const unsigned int)
+v2di __builtin_ia32_insertq (v2di, v2di)
+v2di __builtin_ia32_insertqi (v2di, v2di, const unsigned int, const unsigned int)
+@end smallexample
+
+The following built-in functions are available when @option{-msse5} is used.
+All of them generate the machine instruction that is part of the name
+with MMX registers.
@smallexample
-void _mm_stream_sd (double*,__m128d);
-Generates the @code{movntsd} machine instruction.
-void _mm_stream_ss (float*,__m128);
-Generates the @code{movntss} machine instruction.
-__m128i _mm_extract_si64 (__m128i, __m128i);
-Generates the @code{extrq} machine instruction with only SSE register operands.
-__m128i _mm_extracti_si64 (__m128i, int, int);
-Generates the @code{extrq} machine instruction with SSE register and immediate operands.
-__m128i _mm_insert_si64 (__m128i, __m128i);
-Generates the @code{insertq} machine instruction with only SSE register operands.
-__m128i _mm_inserti_si64 (__m128i, __m128i, int, int);
-Generates the @code{insertq} machine instruction with SSE register and immediate operands.
+v2df __builtin_ia32_comeqpd (v2df, v2df)
+v2df __builtin_ia32_comeqps (v2df, v2df)
+v4sf __builtin_ia32_comeqsd (v4sf, v4sf)
+v4sf __builtin_ia32_comeqss (v4sf, v4sf)
+v2df __builtin_ia32_comfalsepd (v2df, v2df)
+v2df __builtin_ia32_comfalseps (v2df, v2df)
+v4sf __builtin_ia32_comfalsesd (v4sf, v4sf)
+v4sf __builtin_ia32_comfalsess (v4sf, v4sf)
+v2df __builtin_ia32_comgepd (v2df, v2df)
+v2df __builtin_ia32_comgeps (v2df, v2df)
+v4sf __builtin_ia32_comgesd (v4sf, v4sf)
+v4sf __builtin_ia32_comgess (v4sf, v4sf)
+v2df __builtin_ia32_comgtpd (v2df, v2df)
+v2df __builtin_ia32_comgtps (v2df, v2df)
+v4sf __builtin_ia32_comgtsd (v4sf, v4sf)
+v4sf __builtin_ia32_comgtss (v4sf, v4sf)
+v2df __builtin_ia32_comlepd (v2df, v2df)
+v2df __builtin_ia32_comleps (v2df, v2df)
+v4sf __builtin_ia32_comlesd (v4sf, v4sf)
+v4sf __builtin_ia32_comless (v4sf, v4sf)
+v2df __builtin_ia32_comltpd (v2df, v2df)
+v2df __builtin_ia32_comltps (v2df, v2df)
+v4sf __builtin_ia32_comltsd (v4sf, v4sf)
+v4sf __builtin_ia32_comltss (v4sf, v4sf)
+v2df __builtin_ia32_comnepd (v2df, v2df)
+v2df __builtin_ia32_comneps (v2df, v2df)
+v4sf __builtin_ia32_comnesd (v4sf, v4sf)
+v4sf __builtin_ia32_comness (v4sf, v4sf)
+v2df __builtin_ia32_comordpd (v2df, v2df)
+v2df __builtin_ia32_comordps (v2df, v2df)
+v4sf __builtin_ia32_comordsd (v4sf, v4sf)
+v4sf __builtin_ia32_comordss (v4sf, v4sf)
+v2df __builtin_ia32_comtruepd (v2df, v2df)
+v2df __builtin_ia32_comtrueps (v2df, v2df)
+v4sf __builtin_ia32_comtruesd (v4sf, v4sf)
+v4sf __builtin_ia32_comtruess (v4sf, v4sf)
+v2df __builtin_ia32_comueqpd (v2df, v2df)
+v2df __builtin_ia32_comueqps (v2df, v2df)
+v4sf __builtin_ia32_comueqsd (v4sf, v4sf)
+v4sf __builtin_ia32_comueqss (v4sf, v4sf)
+v2df __builtin_ia32_comugepd (v2df, v2df)
+v2df __builtin_ia32_comugeps (v2df, v2df)
+v4sf __builtin_ia32_comugesd (v4sf, v4sf)
+v4sf __builtin_ia32_comugess (v4sf, v4sf)
+v2df __builtin_ia32_comugtpd (v2df, v2df)
+v2df __builtin_ia32_comugtps (v2df, v2df)
+v4sf __builtin_ia32_comugtsd (v4sf, v4sf)
+v4sf __builtin_ia32_comugtss (v4sf, v4sf)
+v2df __builtin_ia32_comulepd (v2df, v2df)
+v2df __builtin_ia32_comuleps (v2df, v2df)
+v4sf __builtin_ia32_comulesd (v4sf, v4sf)
+v4sf __builtin_ia32_comuless (v4sf, v4sf)
+v2df __builtin_ia32_comultpd (v2df, v2df)
+v2df __builtin_ia32_comultps (v2df, v2df)
+v4sf __builtin_ia32_comultsd (v4sf, v4sf)
+v4sf __builtin_ia32_comultss (v4sf, v4sf)
+v2df __builtin_ia32_comunepd (v2df, v2df)
+v2df __builtin_ia32_comuneps (v2df, v2df)
+v4sf __builtin_ia32_comunesd (v4sf, v4sf)
+v4sf __builtin_ia32_comuness (v4sf, v4sf)
+v2df __builtin_ia32_comunordpd (v2df, v2df)
+v2df __builtin_ia32_comunordps (v2df, v2df)
+v4sf __builtin_ia32_comunordsd (v4sf, v4sf)
+v4sf __builtin_ia32_comunordss (v4sf, v4sf)
+v2df __builtin_ia32_fmaddpd (v2df, v2df, v2df)
+v4sf __builtin_ia32_fmaddps (v4sf, v4sf, v4sf)
+v2df __builtin_ia32_fmaddsd (v2df, v2df, v2df)
+v4sf __builtin_ia32_fmaddss (v4sf, v4sf, v4sf)
+v2df __builtin_ia32_fmsubpd (v2df, v2df, v2df)
+v4sf __builtin_ia32_fmsubps (v4sf, v4sf, v4sf)
+v2df __builtin_ia32_fmsubsd (v2df, v2df, v2df)
+v4sf __builtin_ia32_fmsubss (v4sf, v4sf, v4sf)
+v2df __builtin_ia32_fnmaddpd (v2df, v2df, v2df)
+v4sf __builtin_ia32_fnmaddps (v4sf, v4sf, v4sf)
+v2df __builtin_ia32_fnmaddsd (v2df, v2df, v2df)
+v4sf __builtin_ia32_fnmaddss (v4sf, v4sf, v4sf)
+v2df __builtin_ia32_fnmsubpd (v2df, v2df, v2df)
+v4sf __builtin_ia32_fnmsubps (v4sf, v4sf, v4sf)
+v2df __builtin_ia32_fnmsubsd (v2df, v2df, v2df)
+v4sf __builtin_ia32_fnmsubss (v4sf, v4sf, v4sf)
+v2df __builtin_ia32_frczpd (v2df)
+v4sf __builtin_ia32_frczps (v4sf)
+v2df __builtin_ia32_frczsd (v2df, v2df)
+v4sf __builtin_ia32_frczss (v4sf, v4sf)
+v2di __builtin_ia32_pcmov (v2di, v2di, v2di)
+v2di __builtin_ia32_pcmov_v2di (v2di, v2di, v2di)
+v4si __builtin_ia32_pcmov_v4si (v4si, v4si, v4si)
+v8hi __builtin_ia32_pcmov_v8hi (v8hi, v8hi, v8hi)
+v16qi __builtin_ia32_pcmov_v16qi (v16qi, v16qi, v16qi)
+v2df __builtin_ia32_pcmov_v2df (v2df, v2df, v2df)
+v4sf __builtin_ia32_pcmov_v4sf (v4sf, v4sf, v4sf)
+v16qi __builtin_ia32_pcomeqb (v16qi, v16qi)
+v8hi __builtin_ia32_pcomeqw (v8hi, v8hi)
+v4si __builtin_ia32_pcomeqd (v4si, v4si)
+v2di __builtin_ia32_pcomeqq (v2di, v2di)
+v16qi __builtin_ia32_pcomequb (v16qi, v16qi)
+v4si __builtin_ia32_pcomequd (v4si, v4si)
+v2di __builtin_ia32_pcomequq (v2di, v2di)
+v8hi __builtin_ia32_pcomequw (v8hi, v8hi)
+v8hi __builtin_ia32_pcomeqw (v8hi, v8hi)
+v16qi __builtin_ia32_pcomfalseb (v16qi, v16qi)
+v4si __builtin_ia32_pcomfalsed (v4si, v4si)
+v2di __builtin_ia32_pcomfalseq (v2di, v2di)
+v16qi __builtin_ia32_pcomfalseub (v16qi, v16qi)
+v4si __builtin_ia32_pcomfalseud (v4si, v4si)
+v2di __builtin_ia32_pcomfalseuq (v2di, v2di)
+v8hi __builtin_ia32_pcomfalseuw (v8hi, v8hi)
+v8hi __builtin_ia32_pcomfalsew (v8hi, v8hi)
+v16qi __builtin_ia32_pcomgeb (v16qi, v16qi)
+v4si __builtin_ia32_pcomged (v4si, v4si)
+v2di __builtin_ia32_pcomgeq (v2di, v2di)
+v16qi __builtin_ia32_pcomgeub (v16qi, v16qi)
+v4si __builtin_ia32_pcomgeud (v4si, v4si)
+v2di __builtin_ia32_pcomgeuq (v2di, v2di)
+v8hi __builtin_ia32_pcomgeuw (v8hi, v8hi)
+v8hi __builtin_ia32_pcomgew (v8hi, v8hi)
+v16qi __builtin_ia32_pcomgtb (v16qi, v16qi)
+v4si __builtin_ia32_pcomgtd (v4si, v4si)
+v2di __builtin_ia32_pcomgtq (v2di, v2di)
+v16qi __builtin_ia32_pcomgtub (v16qi, v16qi)
+v4si __builtin_ia32_pcomgtud (v4si, v4si)
+v2di __builtin_ia32_pcomgtuq (v2di, v2di)
+v8hi __builtin_ia32_pcomgtuw (v8hi, v8hi)
+v8hi __builtin_ia32_pcomgtw (v8hi, v8hi)
+v16qi __builtin_ia32_pcomleb (v16qi, v16qi)
+v4si __builtin_ia32_pcomled (v4si, v4si)
+v2di __builtin_ia32_pcomleq (v2di, v2di)
+v16qi __builtin_ia32_pcomleub (v16qi, v16qi)
+v4si __builtin_ia32_pcomleud (v4si, v4si)
+v2di __builtin_ia32_pcomleuq (v2di, v2di)
+v8hi __builtin_ia32_pcomleuw (v8hi, v8hi)
+v8hi __builtin_ia32_pcomlew (v8hi, v8hi)
+v16qi __builtin_ia32_pcomltb (v16qi, v16qi)
+v4si __builtin_ia32_pcomltd (v4si, v4si)
+v2di __builtin_ia32_pcomltq (v2di, v2di)
+v16qi __builtin_ia32_pcomltub (v16qi, v16qi)
+v4si __builtin_ia32_pcomltud (v4si, v4si)
+v2di __builtin_ia32_pcomltuq (v2di, v2di)
+v8hi __builtin_ia32_pcomltuw (v8hi, v8hi)
+v8hi __builtin_ia32_pcomltw (v8hi, v8hi)
+v16qi __builtin_ia32_pcomneb (v16qi, v16qi)
+v4si __builtin_ia32_pcomned (v4si, v4si)
+v2di __builtin_ia32_pcomneq (v2di, v2di)
+v16qi __builtin_ia32_pcomneub (v16qi, v16qi)
+v4si __builtin_ia32_pcomneud (v4si, v4si)
+v2di __builtin_ia32_pcomneuq (v2di, v2di)
+v8hi __builtin_ia32_pcomneuw (v8hi, v8hi)
+v8hi __builtin_ia32_pcomnew (v8hi, v8hi)
+v16qi __builtin_ia32_pcomtrueb (v16qi, v16qi)
+v4si __builtin_ia32_pcomtrued (v4si, v4si)
+v2di __builtin_ia32_pcomtrueq (v2di, v2di)
+v16qi __builtin_ia32_pcomtrueub (v16qi, v16qi)
+v4si __builtin_ia32_pcomtrueud (v4si, v4si)
+v2di __builtin_ia32_pcomtrueuq (v2di, v2di)
+v8hi __builtin_ia32_pcomtrueuw (v8hi, v8hi)
+v8hi __builtin_ia32_pcomtruew (v8hi, v8hi)
+v4df __builtin_ia32_permpd (v2df, v2df, v16qi)
+v4sf __builtin_ia32_permps (v4sf, v4sf, v16qi)
+v4si __builtin_ia32_phaddbd (v16qi)
+v2di __builtin_ia32_phaddbq (v16qi)
+v8hi __builtin_ia32_phaddbw (v16qi)
+v2di __builtin_ia32_phadddq (v4si)
+v4si __builtin_ia32_phaddubd (v16qi)
+v2di __builtin_ia32_phaddubq (v16qi)
+v8hi __builtin_ia32_phaddubw (v16qi)
+v2di __builtin_ia32_phaddudq (v4si)
+v4si __builtin_ia32_phadduwd (v8hi)
+v2di __builtin_ia32_phadduwq (v8hi)
+v4si __builtin_ia32_phaddwd (v8hi)
+v2di __builtin_ia32_phaddwq (v8hi)
+v8hi __builtin_ia32_phsubbw (v16qi)
+v2di __builtin_ia32_phsubdq (v4si)
+v4si __builtin_ia32_phsubwd (v8hi)
+v4si __builtin_ia32_pmacsdd (v4si, v4si, v4si)
+v2di __builtin_ia32_pmacsdqh (v4si, v4si, v2di)
+v2di __builtin_ia32_pmacsdql (v4si, v4si, v2di)
+v4si __builtin_ia32_pmacssdd (v4si, v4si, v4si)
+v2di __builtin_ia32_pmacssdqh (v4si, v4si, v2di)
+v2di __builtin_ia32_pmacssdql (v4si, v4si, v2di)
+v4si __builtin_ia32_pmacsswd (v8hi, v8hi, v4si)
+v8hi __builtin_ia32_pmacssww (v8hi, v8hi, v8hi)
+v4si __builtin_ia32_pmacswd (v8hi, v8hi, v4si)
+v8hi __builtin_ia32_pmacsww (v8hi, v8hi, v8hi)
+v4si __builtin_ia32_pmadcsswd (v8hi, v8hi, v4si)
+v4si __builtin_ia32_pmadcswd (v8hi, v8hi, v4si)
+v16qi __builtin_ia32_pperm (v16qi, v16qi, v16qi)
+v16qi __builtin_ia32_protb (v16qi, v16qi)
+v4si __builtin_ia32_protd (v4si, v4si)
+v2di __builtin_ia32_protq (v2di, v2di)
+v8hi __builtin_ia32_protw (v8hi, v8hi)
+v16qi __builtin_ia32_pshab (v16qi, v16qi)
+v4si __builtin_ia32_pshad (v4si, v4si)
+v2di __builtin_ia32_pshaq (v2di, v2di)
+v8hi __builtin_ia32_pshaw (v8hi, v8hi)
+v16qi __builtin_ia32_pshlb (v16qi, v16qi)
+v4si __builtin_ia32_pshld (v4si, v4si)
+v2di __builtin_ia32_pshlq (v2di, v2di)
+v8hi __builtin_ia32_pshlw (v8hi, v8hi)
+@end smallexample
+
+The following builtin-in functions are available when @option{-msse5}
+is used. The second argument must be an integer constant and generate
+the machine instruction that is part of the name with the @samp{_imm}
+suffix removed.
+
+@smallexample
+v16qi __builtin_ia32_protb_imm (v16qi, int)
+v4si __builtin_ia32_protd_imm (v4si, int)
+v2di __builtin_ia32_protq_imm (v2di, int)
+v8hi __builtin_ia32_protw_imm (v8hi, int)
@end smallexample
The following built-in functions are available when @option{-m3dnow} is used.
* Weak Pragmas::
* Diagnostic Pragmas::
* Visibility Pragmas::
+* Push/Pop Macro Pragmas::
@end menu
@node ARM Pragmas
declarations.
@end table
-@c Describe c4x pragmas here.
@c Describe h8300 pragmas here.
@c Describe sh pragmas here.
@c Describe v850 pragmas here.
Increase the minimum alignment of each @var{variable} to @var{alignment}.
This is the same as GCC's @code{aligned} attribute @pxref{Variable
Attributes}). Macro expansion occurs on the arguments to this pragma
-when compiling C and Objective-C. It does not currently occur when
+when compiling C and Objective-C@. It does not currently occur when
compiling C++, but this is a bug which may be fixed in a future
release.
@node Structure-Packing Pragmas
@subsection Structure-Packing Pragmas
-For compatibility with Win32, GCC supports a set of @code{#pragma}
-directives which change the maximum alignment of members of structures
-(other than zero-width bitfields), unions, and classes subsequently
-defined. The @var{n} value below always is required to be a small power
-of two and specifies the new alignment in bytes.
+For compatibility with Microsoft Windows compilers, GCC supports a
+set of @code{#pragma} directives which change the maximum alignment of
+members of structures (other than zero-width bitfields), unions, and
+classes subsequently defined. The @var{n} value below always is required
+to be a small power of two and specifies the new alignment in bytes.
@enumerate
@item @code{#pragma pack(@var{n})} simply sets the new alignment.
@code{#pragma pack(pop)}.
@end enumerate
-Some targets, e.g. i386 and powerpc, support the @code{ms_struct}
+Some targets, e.g.@: i386 and powerpc, support the @code{ms_struct}
@code{#pragma} which lays out a structure as the documented
@code{__attribute__ ((ms_struct))}.
@enumerate
Modifies the disposition of a diagnostic. Note that not all
diagnostics are modifiable; at the moment only warnings (normally
-controlled by @samp{-W...}) can be controlled, and not all of them.
+controlled by @samp{-W@dots{}}) can be controlled, and not all of them.
Use @option{-fdiagnostics-show-option} to determine which diagnostics
are controllable and which option controls them.
@end table
+
+@node Push/Pop Macro Pragmas
+@subsection Push/Pop Macro Pragmas
+
+For compatibility with Microsoft Windows compilers, GCC supports
+@samp{#pragma push_macro(@var{"macro_name"})}
+and @samp{#pragma pop_macro(@var{"macro_name"})}.
+
+@table @code
+@item #pragma push_macro(@var{"macro_name"})
+@cindex pragma, push_macro
+This pragma saves the value of the macro named as @var{macro_name} to
+the top of the stack for this macro.
+
+@item #pragma pop_macro(@var{"macro_name"})
+@cindex pragma, pop_macro
+This pragma sets the value of the macro named as @var{macro_name} to
+the value on top of the stack for this macro. If the stack for
+@var{macro_name} is empty, the value of the macro remains unchanged.
+@end table
+
+For example:
+
+@smallexample
+#define X 1
+#pragma push_macro("X")
+#undef X
+#define X -1
+#pragma pop_macro("X")
+int x [X];
+@end smallexample
+
+In this example, the definition of X as 1 is saved by @code{#pragma
+push_macro} and restored by @code{#pragma pop_macro}.
+
@node Unnamed Fields
@section Unnamed struct/union fields within structs/unions
@cindex struct
@end quotation
@end itemize
+@node Binary constants
+@section Binary constants using the @samp{0b} prefix
+@cindex Binary constants using the @samp{0b} prefix
+
+Integer constants can be written as binary constants, consisting of a
+sequence of @samp{0} and @samp{1} digits, prefixed by @samp{0b} or
+@samp{0B}. This is particularly useful in environments that operate a
+lot on the bit-level (like microcontrollers).
+
+The following statements are identical:
+
+@smallexample
+i = 42;
+i = 0x2a;
+i = 052;
+i = 0b101010;
+@end smallexample
+
+The type of these constants follows the same rules as for octal or
+hexadecimal integer constants, so suffixes like @samp{L} or @samp{UL}
+can be applied.
+
@node C++ Extensions
@chapter Extensions to the C++ Language
@cindex extensions, C++ language
method denoted by a @samp{->*} or @samp{.*} expression.
* C++ Attributes:: Variable, function, and type attributes for C++ only.
* Namespace Association:: Strong using-directives for namespace association.
+* Type Traits:: Compiler support for type traits
* Java Exceptions:: Tweaking exception handling to work with Java.
* Deprecated Features:: Things will disappear from g++.
* Backwards Compatibility:: Compatibilities with earlier definitions of C++.
because otherwise certain simple expressions become undefined. However,
because it would surprise most programmers, G++ treats dereferencing a
pointer to volatile object of complete type when the value is unused as
-GCC would do for an equivalent type in C. When the object has incomplete
+GCC would do for an equivalent type in C@. When the object has incomplete
type, G++ issues a warning; if you wish to force an error, you must
force a conversion to rvalue with, for instance, a static cast.
@}
@end smallexample
+@node Type Traits
+@section Type Traits
+
+The C++ front-end implements syntactic extensions that allow to
+determine at compile time various characteristics of a type (or of a
+pair of types).
+
+@table @code
+@item __has_nothrow_assign (type)
+If @code{type} is const qualified or is a reference type then the trait is
+false. Otherwise if @code{__has_trivial_assign (type)} is true then the trait
+is true, else if @code{type} is a cv class or union type with copy assignment
+operators that are known not to throw an exception then the trait is true,
+else it is false. Requires: @code{type} shall be a complete type, an array
+type of unknown bound, or is a @code{void} type.
+
+@item __has_nothrow_copy (type)
+If @code{__has_trivial_copy (type)} is true then the trait is true, else if
+@code{type} is a cv class or union type with copy constructors that
+are known not to throw an exception then the trait is true, else it is false.
+Requires: @code{type} shall be a complete type, an array type of
+unknown bound, or is a @code{void} type.
+
+@item __has_nothrow_constructor (type)
+If @code{__has_trivial_constructor (type)} is true then the trait is
+true, else if @code{type} is a cv class or union type (or array
+thereof) with a default constructor that is known not to throw an
+exception then the trait is true, else it is false. Requires:
+@code{type} shall be a complete type, an array type of unknown bound,
+or is a @code{void} type.
+
+@item __has_trivial_assign (type)
+If @code{type} is const qualified or is a reference type then the trait is
+false. Otherwise if @code{__is_pod (type)} is true then the trait is
+true, else if @code{type} is a cv class or union type with a trivial
+copy assignment ([class.copy]) then the trait is true, else it is
+false. Requires: @code{type} shall be a complete type, an array type
+of unknown bound, or is a @code{void} type.
+
+@item __has_trivial_copy (type)
+If @code{__is_pod (type)} is true or @code{type} is a reference type
+then the trait is true, else if @code{type} is a cv class or union type
+with a trivial copy constructor ([class.copy]) then the trait
+is true, else it is false. Requires: @code{type} shall be a complete
+type, an array type of unknown bound, or is a @code{void} type.
+
+@item __has_trivial_constructor (type)
+If @code{__is_pod (type)} is true then the trait is true, else if
+@code{type} is a cv class or union type (or array thereof) with a
+trivial default constructor ([class.ctor]) then the trait is true,
+else it is false. Requires: @code{type} shall be a complete type, an
+array type of unknown bound, or is a @code{void} type.
+
+@item __has_trivial_destructor (type)
+If @code{__is_pod (type)} is true or @code{type} is a reference type then
+the trait is true, else if @code{type} is a cv class or union type (or
+array thereof) with a trivial destructor ([class.dtor]) then the trait
+is true, else it is false. Requires: @code{type} shall be a complete
+type, an array type of unknown bound, or is a @code{void} type.
+
+@item __has_virtual_destructor (type)
+If @code{type} is a class type with a virtual destructor
+([class.dtor]) then the trait is true, else it is false. Requires:
+@code{type} shall be a complete type, an array type of unknown bound,
+or is a @code{void} type.
+
+@item __is_abstract (type)
+If @code{type} is an abstract class ([class.abstract]) then the trait
+is true, else it is false. Requires: @code{type} shall be a complete
+type, an array type of unknown bound, or is a @code{void} type.
+
+@item __is_base_of (base_type, derived_type)
+If @code{base_type} is a base class of @code{derived_type}
+([class.derived]) then the trait is true, otherwise it is false.
+Top-level cv qualifications of @code{base_type} and
+@code{derived_type} are ignored. For the purposes of this trait, a
+class type is considered is own base. Requires: if @code{__is_class
+(base_type)} and @code{__is_class (derived_type)} are true and
+@code{base_type} and @code{derived_type} are not the same type
+(disregarding cv-qualifiers), @code{derived_type} shall be a complete
+type. Diagnostic is produced if this requirement is not met.
+
+@item __is_class (type)
+If @code{type} is a cv class type, and not a union type
+([basic.compound]) the the trait is true, else it is false.
+
+@item __is_empty (type)
+If @code{__is_class (type)} is false then the trait is false.
+Otherwise @code{type} is considered empty if and only if: @code{type}
+has no non-static data members, or all non-static data members, if
+any, are bit-fields of lenght 0, and @code{type} has no virtual
+members, and @code{type} has no virtual base classes, and @code{type}
+has no base classes @code{base_type} for which
+@code{__is_empty (base_type)} is false. Requires: @code{type} shall
+be a complete type, an array type of unknown bound, or is a
+@code{void} type.
+
+@item __is_enum (type)
+If @code{type} is a cv enumeration type ([basic.compound]) the the trait is
+true, else it is false.
+
+@item __is_pod (type)
+If @code{type} is a cv POD type ([basic.types]) then the trait is true,
+else it is false. Requires: @code{type} shall be a complete type,
+an array type of unknown bound, or is a @code{void} type.
+
+@item __is_polymorphic (type)
+If @code{type} is a polymorphic class ([class.virtual]) then the trait
+is true, else it is false. Requires: @code{type} shall be a complete
+type, an array type of unknown bound, or is a @code{void} type.
+
+@item __is_union (type)
+If @code{type} is a cv union type ([basic.compound]) the the trait is
+true, else it is false.
+
+@end table
+
@node Java Exceptions
@section Java Exceptions
The G++ minimum and maximum operators (@samp{<?} and @samp{>?}) and
their compound forms (@samp{<?=}) and @samp{>?=}) have been deprecated
-and will be removed in a future version. Code using these operators
-should be modified to use @code{std::min} and @code{std::max} instead.
+and are now removed from G++. Code using these operators should be
+modified to use @code{std::min} and @code{std::max} instead.
The named return value extension has been deprecated, and is now
removed from G++.
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