path: root/misc/sys/cdefs.h

/* Copyright (C) 1992-2023 Free Software Foundation, Inc.
   Copyright The GNU Toolchain Authors.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef	_SYS_CDEFS_H
#define	_SYS_CDEFS_H	1

/* We are almost always included from features.h. */
#ifndef _FEATURES_H
# include <features.h>
#endif

/* The GNU libc does not support any K&R compilers or the traditional mode
   of ISO C compilers anymore.  Check for some of the combinations not
   supported anymore.  */
#if defined __GNUC__ && !defined __STDC__ && !defined __cplusplus
# error "You need a ISO C or C++ conforming compiler to use the glibc headers"
#endif

/* Some user header file might have defined this before.  */
#undef	__P
#undef	__PMT

/* Compilers that lack __has_attribute may object to
       #if defined __has_attribute && __has_attribute (...)
   even though they do not need to evaluate the right-hand side of the &&.
   Similarly for __has_builtin, etc.  */
#if (defined __has_attribute \
     && (!defined __clang_minor__ \
         || 3 < __clang_major__ + (5 <= __clang_minor__)))
# define __glibc_has_attribute(attr) __has_attribute (attr)
#else
# define __glibc_has_attribute(attr) 0
#endif
#ifdef __has_builtin
# define __glibc_has_builtin(name) __has_builtin (name)
#else
# define __glibc_has_builtin(name) 0
#endif
#ifdef __has_extension
# define __glibc_has_extension(ext) __has_extension (ext)
#else
# define __glibc_has_extension(ext) 0
#endif

#if defined __GNUC__ || defined __clang__

/* All functions, except those with callbacks or those that
   synchronize memory, are leaf functions.  */
# if __GNUC_PREREQ (4, 6) && !defined _LIBC
#  define __LEAF , __leaf__
#  define __LEAF_ATTR __attribute__ ((__leaf__))
# else
#  define __LEAF
#  define __LEAF_ATTR
# endif

/* GCC can always grok prototypes.  For C++ programs we add throw()
   to help it optimize the function calls.  But this only works with
   gcc 2.8.x and egcs.  For gcc 3.4 and up we even mark C functions
   as non-throwing using a function attribute since programs can use
   the -fexceptions options for C code as well.  */
# if !defined __cplusplus \
     && (__GNUC_PREREQ (3, 4) || __glibc_has_attribute (__nothrow__))
#  define __THROW	__attribute__ ((__nothrow__ __LEAF))
#  define __THROWNL	__attribute__ ((__nothrow__))
#  define __NTH(fct)	__attribute__ ((__nothrow__ __LEAF)) fct
#  define __NTHNL(fct)  __attribute__ ((__nothrow__)) fct
# else
#  if defined __cplusplus && (__GNUC_PREREQ (2,8) || __clang_major >= 4)
#   if __cplusplus >= 201103L
#    define __THROW	noexcept (true)
#   else
#    define __THROW	throw ()
#   endif
#   define __THROWNL	__THROW
#   define __NTH(fct)	__LEAF_ATTR fct __THROW
#   define __NTHNL(fct) fct __THROW
#  else
#   define __THROW
#   define __THROWNL
#   define __NTH(fct)	fct
#   define __NTHNL(fct) fct
#  endif
# endif

#else	/* Not GCC or clang.  */

# if (defined __cplusplus						\
      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
#  define __inline	inline
# else
#  define __inline		/* No inline functions.  */
# endif

# define __THROW
# define __THROWNL
# define __NTH(fct)	fct

#endif	/* GCC || clang.  */

/* These two macros are not used in glibc anymore.  They are kept here
   only because some other projects expect the macros to be defined.  */
#define __P(args)	args
#define __PMT(args)	args

/* For these things, GCC behaves the ANSI way normally,
   and the non-ANSI way under -traditional.  */

#define __CONCAT(x,y)	x ## y
#define __STRING(x)	#x

/* This is not a typedef so `const __ptr_t' does the right thing.  */
#define __ptr_t void *


/* C++ needs to know that types and declarations are C, not C++.  */
#ifdef	__cplusplus
# define __BEGIN_DECLS	extern "C" {
# define __END_DECLS	}
#else
# define __BEGIN_DECLS
# define __END_DECLS
#endif


/* Fortify support.  */
#define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
#define __bos0(ptr) __builtin_object_size (ptr, 0)

/* Use __builtin_dynamic_object_size at _FORTIFY_SOURCE=3 when available.  */
#if __USE_FORTIFY_LEVEL == 3 && (__glibc_clang_prereq (9, 0)		      \
				 || __GNUC_PREREQ (12, 0))
# define __glibc_objsize0(__o) __builtin_dynamic_object_size (__o, 0)
# define __glibc_objsize(__o) __builtin_dynamic_object_size (__o, 1)
#else
# define __glibc_objsize0(__o) __bos0 (__o)
# define __glibc_objsize(__o) __bos (__o)
#endif

/* Compile time conditions to choose between the regular, _chk and _chk_warn
   variants.  These conditions should get evaluated to constant and optimized
   away.  */

#define __glibc_safe_len_cond(__l, __s, __osz) ((__l) <= (__osz) / (__s))
#define __glibc_unsigned_or_positive(__l) \
  ((__typeof (__l)) 0 < (__typeof (__l)) -1				      \
   || (__builtin_constant_p (__l) && (__l) > 0))

/* Length is known to be safe at compile time if the __L * __S <= __OBJSZ
   condition can be folded to a constant and if it is true, or unknown (-1) */
#define __glibc_safe_or_unknown_len(__l, __s, __osz) \
  ((__builtin_constant_p (__osz) && (__osz) == (__SIZE_TYPE__) -1)	      \
   || (__glibc_unsigned_or_positive (__l)				      \
       && __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), \
						       (__s), (__osz)))	      \
       && __glibc_safe_len_cond ((__SIZE_TYPE__) (__l), (__s), (__osz))))

/* Conversely, we know at compile time that the length is unsafe if the
   __L * __S <= __OBJSZ condition can be folded to a constant and if it is
   false.  */
#define __glibc_unsafe_len(__l, __s, __osz) \
  (__glibc_unsigned_or_positive (__l)					      \
   && __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l),     \
						   __s, __osz))		      \
   && !__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), __s, __osz))

/* Fortify function f.  __f_alias, __f_chk and __f_chk_warn must be
   declared.  */

#define __glibc_fortify(f, __l, __s, __osz, ...) \
  (__glibc_safe_or_unknown_len (__l, __s, __osz)			      \
   ? __ ## f ## _alias (__VA_ARGS__)					      \
   : (__glibc_unsafe_len (__l, __s, __osz)				      \
      ? __ ## f ## _chk_warn (__VA_ARGS__, __osz)			      \
      : __ ## f ## _chk (__VA_ARGS__, __osz)))			      \

/* Fortify function f, where object size argument passed to f is the number of
   elements and not total size.  */

#define __glibc_fortify_n(f, __l, __s, __osz, ...) \
  (__glibc_safe_or_unknown_len (__l, __s, __osz)			      \
   ? __ ## f ## _alias (__VA_ARGS__)					      \
   : (__glibc_unsafe_len (__l, __s, __osz)				      \
      ? __ ## f ## _chk_warn (__VA_ARGS__, (__osz) / (__s))		      \
      : __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s))))		      \

#if __GNUC_PREREQ (4,3)
# define __warnattr(msg) __attribute__((__warning__ (msg)))
# define __errordecl(name, msg) \
  extern void name (void) __attribute__((__error__ (msg)))
#else
# define __warnattr(msg)
# define __errordecl(name, msg) extern void name (void)
#endif

/* Support for flexible arrays.
   Headers that should use flexible arrays only if they're "real"
   (e.g. only if they won't affect sizeof()) should test
   #if __glibc_c99_flexarr_available.  */
#if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L && !defined __HP_cc
# define __flexarr	[]
# define __glibc_c99_flexarr_available 1
#elif __GNUC_PREREQ (2,97) || defined __clang__
/* GCC 2.97 and clang support C99 flexible array members as an extension,
   even when in C89 mode or compiling C++ (any version).  */
# define __flexarr	[]
# define __glibc_c99_flexarr_available 1
#elif defined __GNUC__
/* Pre-2.97 GCC did not support C99 flexible arrays but did have
   an equivalent extension with slightly different notation.  */
# define __flexarr	[0]
# d