posix_features.hpp

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//  (C) Copyright John Maddock 2001 - 2003.
//  Use, modification and distribution are subject to the
//  Boost Software License, Version 1.0. (See accompanying file
//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
//  See http://www.boost.org for most recent version.
 
// All POSIX feature tests go in this file,
// Note that we test _POSIX_C_SOURCE and _XOPEN_SOURCE as well
// _POSIX_VERSION and _XOPEN_VERSION: on some systems POSIX API's
// may be present but none-functional unless _POSIX_C_SOURCE and
// _XOPEN_SOURCE have been defined to the right value (it's up
// to the user to do this *before* including any header, although
// in most cases the compiler will do this for you).
 
#if defined(BOOST_HAS_UNISTD_H)
#  include <unistd.h>
 
// XOpen has <nl_types.h>, but is this the correct version check?
#  if defined(_XOPEN_VERSION) && (_XOPEN_VERSION >= 3)
#    define BOOST_HAS_NL_TYPES_H
#  endif
 
// POSIX version 6 requires <stdint.h>
#  if defined(_POSIX_VERSION) && (_POSIX_VERSION >= 200100)
#    define BOOST_HAS_STDINT_H
#  endif
 
// POSIX version 2 requires <dirent.h>
#  if defined(_POSIX_VERSION) && (_POSIX_VERSION >= 199009L)
#    define BOOST_HAS_DIRENT_H
#  endif
 
// POSIX version 3 requires <signal.h> to have sigaction:
#  if defined(_POSIX_VERSION) && (_POSIX_VERSION >= 199506L)
#    define BOOST_HAS_SIGACTION
#  endif
// POSIX defines _POSIX_THREADS > 0 for pthread support,
// however some platforms define _POSIX_THREADS without
// a value, hence the (_POSIX_THREADS+0 >= 0) check.
// Strictly speaking this may catch platforms with a
// non-functioning stub <pthreads.h>, but such occurrences should
// occur very rarely if at all.
#  if defined(_POSIX_THREADS) && (_POSIX_THREADS + 0 >= 0) &&                  \
    !defined(BOOST_HAS_WINTHREADS) && !defined(BOOST_HAS_MPTASKS)
#    define BOOST_HAS_PTHREADS
#  endif
 
// BOOST_HAS_NANOSLEEP:
// This is predicated on _POSIX_TIMERS or _XOPEN_REALTIME:
#  if (defined(_POSIX_TIMERS) && (_POSIX_TIMERS + 0 >= 0)) ||                  \
    (defined(_XOPEN_REALTIME) && (_XOPEN_REALTIME + 0 >= 0))
#    define BOOST_HAS_NANOSLEEP
#  endif
 
// BOOST_HAS_CLOCK_GETTIME:
// This is predicated on _POSIX_TIMERS (also on _XOPEN_REALTIME
// but at least one platform - linux - defines that flag without
// defining clock_gettime):
#  if (defined(_POSIX_TIMERS) && (_POSIX_TIMERS + 0 >= 0))
#    define BOOST_HAS_CLOCK_GETTIME
#  endif
 
// BOOST_HAS_SCHED_YIELD:
// This is predicated on _POSIX_PRIORITY_SCHEDULING or
// on _POSIX_THREAD_PRIORITY_SCHEDULING or on _XOPEN_REALTIME.
#  if defined(_POSIX_PRIORITY_SCHEDULING) &&                                   \
      (_POSIX_PRIORITY_SCHEDULING + 0 > 0) ||                                  \
    (defined(_POSIX_THREAD_PRIORITY_SCHEDULING) &&                             \
     (_POSIX_THREAD_PRIORITY_SCHEDULING + 0 > 0)) ||                           \
    (defined(_XOPEN_REALTIME) && (_XOPEN_REALTIME + 0 >= 0))
#    define BOOST_HAS_SCHED_YIELD
#  endif
 
// BOOST_HAS_GETTIMEOFDAY:
// BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE:
// These are predicated on _XOPEN_VERSION, and appears to be first released
// in issue 4, version 2 (_XOPEN_VERSION > 500).
// Likewise for the functions log1p and expm1.
#  if defined(_XOPEN_VERSION) && (_XOPEN_VERSION + 0 >= 500)
#    define BOOST_HAS_GETTIMEOFDAY
#    if defined(_XOPEN_SOURCE) && (_XOPEN_SOURCE + 0 >= 500)
#      define BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE
#    endif
#    ifndef BOOST_HAS_LOG1P
#      define BOOST_HAS_LOG1P
#    endif
#    ifndef BOOST_HAS_EXPM1
#      define BOOST_HAS_EXPM1
#    endif
#  endif
 
#endif