src/pulse/gccmacro.h

#ifndef foopulsegccmacrohfoo
#define foopulsegccmacrohfoo

/***
  This file is part of PulseAudio.

  Copyright 2004-2006 Lennart Poettering

  PulseAudio 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.

  PulseAudio 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
  General Public License for more details.

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

/** \file
 * GCC attribute macros */

#if defined(__GNUC__)
#ifdef __MINGW32__
#include <stdio.h>
#define PA_GCC_PRINTF_ATTR(a,b) __attribute__ ((format (__MINGW_PRINTF_FORMAT, a, b)))
#else
#define PA_GCC_PRINTF_ATTR(a,b) __attribute__ ((format (printf, a, b)))
#endif
#else
/** If we're in GNU C, use some magic for detecting invalid format strings */
#define PA_GCC_PRINTF_ATTR(a,b)
#endif

#if defined(__GNUC__) && (__GNUC__ >= 4)
#define PA_GCC_SENTINEL __attribute__ ((sentinel))
#else
/** Macro for usage of GCC's sentinel compilation warnings */
#define PA_GCC_SENTINEL
#endif

#ifdef __GNUC__
#define PA_GCC_NORETURN __attribute__((noreturn))
#else
/** Macro for no-return functions */
#define PA_GCC_NORETURN
#endif

#ifdef __GNUC__
#define PA_GCC_UNUSED __attribute__ ((unused))
#else
/** Macro for not used function, variable or parameter */
#define PA_GCC_UNUSED
#endif

#ifdef __GNUC__
#define PA_GCC_DESTRUCTOR __attribute__ ((destructor))
#else
/** Call this function when process terminates */
#define PA_GCC_DESTRUCTOR
#endif

#ifndef PA_GCC_PURE
#ifdef __GNUC__
#define PA_GCC_PURE __attribute__ ((pure))
#else
/** This function's return value depends only the arguments list and global state **/
#define PA_GCC_PURE
#endif
#endif

#ifndef PA_GCC_CONST
#ifdef __GNUC__
#define PA_GCC_CONST __attribute__ ((const))
#else
/** This function's return value depends only the arguments list (stricter version of PA_GCC_PURE) **/
#define PA_GCC_CONST
#endif
#endif

#ifndef PA_GCC_DEPRECATED
#ifdef __GNUC__
#define PA_GCC_DEPRECATED __attribute__ ((deprecated))
#else
/** This function is deprecated **/
#define PA_GCC_DEPRECATED
#endif
#endif

#ifndef PA_GCC_PACKED
#ifdef __GNUC__
#define PA_GCC_PACKED __attribute__ ((packed))
#else
/** Structure shall be packed in memory **/
#define PA_GCC_PACKED
#endif
#endif

#ifndef PA_GCC_ALLOC_SIZE
#if defined(__GNUC__) && (__GNUC__ >= 4) && (__GNUC_MINOR__ >= 3)
#define PA_GCC_ALLOC_SIZE(x) __attribute__ ((__alloc_size__(x)))
#define PA_GCC_ALLOC_SIZE2(x,y) __attribute__ ((__alloc_size__(x,y)))
#else
/** Macro for usage of GCC's alloc_size attribute */
#define PA_GCC_ALLOC_SIZE(x)
/** Macro for usage of GCC's alloc_size attribute */
#define PA_GCC_ALLOC_SIZE2(x,y)
#endif
#endif

#ifndef PA_GCC_MALLOC
#ifdef __GNUC__
#define PA_GCC_MALLOC __attribute__ ((malloc))
#else
/** Macro for usage of GCC's malloc attribute */
#define PA_GCC_MALLOC
#endif
#endif

#ifndef PA_GCC_WEAKREF
#if defined(__GNUC__) && defined(__ELF__) && (((__GNUC__ == 4) && (__GNUC_MINOR__ > 1)) || (__GNUC__ > 4))
/** Macro for usage of GCC's weakref attribute */
#define PA_GCC_WEAKREF(x) __attribute__((weakref(#x)))
#endif
#endif

#ifndef PA_LIKELY
#ifdef __GNUC__
#define PA_LIKELY(x) (__builtin_expect(!!(x),1))
#define PA_UNLIKELY(x) (__builtin_expect(!!(x),0))
#else
#define PA_LIKELY(x) (x)
#define PA_UNLIKELY(x) (x)
#endif
#endif

#ifdef __GNUC__
#define PA_CLAMP(x, low, high)                                          \
    __extension__ ({                                                    \
            typeof(x) _x = (x);                                         \
            typeof(low) _low = (low);                                   \
            typeof(high) _high = (high);                                \
            ((_x > _high) ? _high : ((_x < _low) ? _low : _x));         \
        })
#else
#define PA_CLAMP(x, low, high) (((x) > (high)) ? (high) : (((x) < (low)) ? (low) : (x)))
#endif

#ifdef __GNUC__
#define PA_CLAMP_UNLIKELY(x, low, high)                                 \
    __extension__ ({                                                    \
            typeof(x) _x = (x);                                         \
            typeof(low) _low = (low);                                   \
            typeof(high) _high = (high);                                \
            (PA_UNLIKELY(_x > _high) ? _high : (PA_UNLIKELY(_x < _low) ? _low : _x)); \
        })
#else
#define PA_CLAMP_UNLIKELY(x, low, high) (PA_UNLIKELY((x) > (high)) ? (high) : (PA_UNLIKELY((x) < (low)) ? (low) : (x)))
#endif

/* We don't define a PA_CLAMP_LIKELY here, because it doesn't really
 * make sense: we cannot know if it is more likely that the value is
 * lower or greater than the boundaries. */

#endif