//  (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