296 lines
9.3 KiB
C
296 lines
9.3 KiB
C
/* ANSI and traditional C compatability macros
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Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001
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Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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/* ANSI and traditional C compatibility macros
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ANSI C is assumed if __STDC__ is #defined.
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Macro ANSI C definition Traditional C definition
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----- ---- - ---------- ----------- - ----------
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ANSI_PROTOTYPES 1 not defined
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PTR `void *' `char *'
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PTRCONST `void *const' `char *'
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LONG_DOUBLE `long double' `double'
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const not defined `'
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volatile not defined `'
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signed not defined `'
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VA_START(ap, var) va_start(ap, var) va_start(ap)
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Note that it is safe to write "void foo();" indicating a function
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with no return value, in all K+R compilers we have been able to test.
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For declaring functions with prototypes, we also provide these:
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PARAMS ((prototype))
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-- for functions which take a fixed number of arguments. Use this
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when declaring the function. When defining the function, write a
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K+R style argument list. For example:
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char *strcpy PARAMS ((char *dest, char *source));
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...
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char *
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strcpy (dest, source)
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char *dest;
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char *source;
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{ ... }
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VPARAMS ((prototype, ...))
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-- for functions which take a variable number of arguments. Use
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PARAMS to declare the function, VPARAMS to define it. For example:
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int printf PARAMS ((const char *format, ...));
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...
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int
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printf VPARAMS ((const char *format, ...))
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{
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...
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}
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For writing functions which take variable numbers of arguments, we
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also provide the VA_OPEN, VA_CLOSE, and VA_FIXEDARG macros. These
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hide the differences between K+R <varargs.h> and C89 <stdarg.h> more
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thoroughly than the simple VA_START() macro mentioned above.
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VA_OPEN and VA_CLOSE are used *instead of* va_start and va_end.
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Immediately after VA_OPEN, put a sequence of VA_FIXEDARG calls
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corresponding to the list of fixed arguments. Then use va_arg
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normally to get the variable arguments, or pass your va_list object
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around. You do not declare the va_list yourself; VA_OPEN does it
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for you.
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Here is a complete example:
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int
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printf VPARAMS ((const char *format, ...))
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{
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int result;
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VA_OPEN (ap, format);
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VA_FIXEDARG (ap, const char *, format);
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result = vfprintf (stdout, format, ap);
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VA_CLOSE (ap);
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return result;
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}
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You can declare variables either before or after the VA_OPEN,
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VA_FIXEDARG sequence. Also, VA_OPEN and VA_CLOSE are the beginning
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and end of a block. They must appear at the same nesting level,
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and any variables declared after VA_OPEN go out of scope at
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VA_CLOSE. Unfortunately, with a K+R compiler, that includes the
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argument list. You can have multiple instances of VA_OPEN/VA_CLOSE
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pairs in a single function in case you need to traverse the
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argument list more than once.
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For ease of writing code which uses GCC extensions but needs to be
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portable to other compilers, we provide the GCC_VERSION macro that
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simplifies testing __GNUC__ and __GNUC_MINOR__ together, and various
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wrappers around __attribute__. Also, __extension__ will be #defined
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to nothing if it doesn't work. See below.
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This header also defines a lot of obsolete macros:
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CONST, VOLATILE, SIGNED, PROTO, EXFUN, DEFUN, DEFUN_VOID,
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AND, DOTS, NOARGS. Don't use them. */
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#ifndef _ANSIDECL_H
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#define _ANSIDECL_H 1
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/* Every source file includes this file,
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so they will all get the switch for lint. */
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/* LINTLIBRARY */
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/* Using MACRO(x,y) in cpp #if conditionals does not work with some
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older preprocessors. Thus we can't define something like this:
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#define HAVE_GCC_VERSION(MAJOR, MINOR) \
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(__GNUC__ > (MAJOR) || (__GNUC__ == (MAJOR) && __GNUC_MINOR__ >= (MINOR)))
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and then test "#if HAVE_GCC_VERSION(2,7)".
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So instead we use the macro below and test it against specific values. */
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/* This macro simplifies testing whether we are using gcc, and if it
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is of a particular minimum version. (Both major & minor numbers are
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significant.) This macro will evaluate to 0 if we are not using
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gcc at all. */
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#ifndef GCC_VERSION
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#define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__)
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#endif /* GCC_VERSION */
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#if defined (__STDC__) || defined (_AIX) || (defined (__mips) && defined (_SYSTYPE_SVR4)) || defined(_WIN32)
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/* All known AIX compilers implement these things (but don't always
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define __STDC__). The RISC/OS MIPS compiler defines these things
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in SVR4 mode, but does not define __STDC__. */
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#define ANSI_PROTOTYPES 1
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#define PTR void *
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#define PTRCONST void *const
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#define LONG_DOUBLE long double
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#define PARAMS(ARGS) ARGS
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#define VPARAMS(ARGS) ARGS
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#define VA_START(VA_LIST, VAR) va_start(VA_LIST, VAR)
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/* variadic function helper macros */
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/* "struct Qdmy" swallows the semicolon after VA_OPEN/VA_FIXEDARG's
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use without inhibiting further decls and without declaring an
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actual variable. */
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#define VA_OPEN(AP, VAR) { va_list AP; va_start(AP, VAR); { struct Qdmy
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#define VA_CLOSE(AP) } va_end(AP); }
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#define VA_FIXEDARG(AP, T, N) struct Qdmy
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#undef const
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#undef volatile
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#undef signed
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/* inline requires special treatment; it's in C99, and GCC >=2.7 supports
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it too, but it's not in C89. */
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#undef inline
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#if __STDC_VERSION__ > 199901L
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/* it's a keyword */
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#else
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# if GCC_VERSION >= 2007
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# define inline __inline__ /* __inline__ prevents -pedantic warnings */
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# else
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# define inline /* nothing */
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# endif
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#endif
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/* These are obsolete. Do not use. */
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#ifndef IN_GCC
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#define CONST const
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#define VOLATILE volatile
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#define SIGNED signed
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#define PROTO(type, name, arglist) type name arglist
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#define EXFUN(name, proto) name proto
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#define DEFUN(name, arglist, args) name(args)
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#define DEFUN_VOID(name) name(void)
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#define AND ,
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#define DOTS , ...
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#define NOARGS void
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#endif /* ! IN_GCC */
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#else /* Not ANSI C. */
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#undef ANSI_PROTOTYPES
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#define PTR char *
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#define PTRCONST PTR
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#define LONG_DOUBLE double
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#define PARAMS(args) ()
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#define VPARAMS(args) (va_alist) va_dcl
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#define VA_START(va_list, var) va_start(va_list)
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#define VA_OPEN(AP, VAR) { va_list AP; va_start(AP); { struct Qdmy
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#define VA_CLOSE(AP) } va_end(AP); }
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#define VA_FIXEDARG(AP, TYPE, NAME) TYPE NAME = va_arg(AP, TYPE)
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/* some systems define these in header files for non-ansi mode */
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#undef const
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#undef volatile
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#undef signed
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#undef inline
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#define const
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#define volatile
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#define signed
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#define inline
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#ifndef IN_GCC
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#define CONST
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#define VOLATILE
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#define SIGNED
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#define PROTO(type, name, arglist) type name ()
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#define EXFUN(name, proto) name()
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#define DEFUN(name, arglist, args) name arglist args;
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#define DEFUN_VOID(name) name()
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#define AND ;
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#define DOTS
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#define NOARGS
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#endif /* ! IN_GCC */
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#endif /* ANSI C. */
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/* Define macros for some gcc attributes. This permits us to use the
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macros freely, and know that they will come into play for the
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version of gcc in which they are supported. */
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#if (GCC_VERSION < 2007)
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# define __attribute__(x)
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#endif
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/* Attribute __malloc__ on functions was valid as of gcc 2.96. */
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#ifndef ATTRIBUTE_MALLOC
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# if (GCC_VERSION >= 2096)
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# define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
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# else
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# define ATTRIBUTE_MALLOC
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# endif /* GNUC >= 2.96 */
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#endif /* ATTRIBUTE_MALLOC */
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/* Attributes on labels were valid as of gcc 2.93. */
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#ifndef ATTRIBUTE_UNUSED_LABEL
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# if (GCC_VERSION >= 2093)
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# define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED
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# else
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# define ATTRIBUTE_UNUSED_LABEL
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# endif /* GNUC >= 2.93 */
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#endif /* ATTRIBUTE_UNUSED_LABEL */
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#ifndef ATTRIBUTE_UNUSED
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#define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
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#endif /* ATTRIBUTE_UNUSED */
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#ifndef ATTRIBUTE_NORETURN
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#define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
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#endif /* ATTRIBUTE_NORETURN */
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#ifndef ATTRIBUTE_PRINTF
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#define ATTRIBUTE_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n)))
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#define ATTRIBUTE_PRINTF_1 ATTRIBUTE_PRINTF(1, 2)
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#define ATTRIBUTE_PRINTF_2 ATTRIBUTE_PRINTF(2, 3)
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#define ATTRIBUTE_PRINTF_3 ATTRIBUTE_PRINTF(3, 4)
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#define ATTRIBUTE_PRINTF_4 ATTRIBUTE_PRINTF(4, 5)
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#define ATTRIBUTE_PRINTF_5 ATTRIBUTE_PRINTF(5, 6)
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#endif /* ATTRIBUTE_PRINTF */
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/* We use __extension__ in some places to suppress -pedantic warnings
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about GCC extensions. This feature didn't work properly before
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gcc 2.8. */
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#if GCC_VERSION < 2008
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#define __extension__
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#endif
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/* Bootstrap support: Adjust certain macros defined by Autoconf,
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which are only valid for the stage1 compiler. If we detect
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a modern version of GCC, we are probably in stage2 or beyond,
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so unconditionally reset the values. Note that const, inline,
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etc. have been dealt with above. */
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#if (GCC_VERSION >= 2007)
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# ifndef HAVE_LONG_DOUBLE
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# define HAVE_LONG_DOUBLE 1
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# endif
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#endif /* GCC >= 2.7 */
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#endif /* ansidecl.h */
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