# serial 36

dnl From Jim Meyering.

dnl Check for the nanosleep function.

dnl If not found, use the supplied replacement.

dnl

# Copyright (C) 1999-2001, 2003-2017 Free Software Foundation, Inc.

# This file is free software; the Free Software Foundation

# gives unlimited permission to copy and/or distribute it,

# with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_FUNC_NANOSLEEP],

[

 AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])

 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

 dnl Persuade glibc and Solaris <time.h> to declare nanosleep.

 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])

 AC_CHECK_HEADERS_ONCE([sys/time.h])

 AC_REQUIRE([gl_FUNC_SELECT])

 nanosleep_save_libs=$LIBS

 # Solaris 2.5.1 needs -lposix4 to get the nanosleep function.

 # Solaris 7 prefers the library name -lrt to the obsolescent name -lposix4.

 LIB_NANOSLEEP=

 AC_SUBST([LIB_NANOSLEEP])

 AC_SEARCH_LIBS([nanosleep], [rt posix4],

                [test "$ac_cv_search_nanosleep" = "none required" ||

                 LIB_NANOSLEEP=$ac_cv_search_nanosleep])

 if test "x$ac_cv_search_nanosleep" != xno; then

   dnl The system has a nanosleep function.

   AC_REQUIRE([gl_MULTIARCH])

   if test $APPLE_UNIVERSAL_BUILD = 1; then

     # A universal build on Apple Mac OS X platforms.

     # The test result would be 'no (mishandles large arguments)' in 64-bit

     # mode but 'yes' in 32-bit mode. But we need a configuration result that

     # is valid in both modes.

     gl_cv_func_nanosleep='no (mishandles large arguments)'

   fi

   AC_CACHE_CHECK([for working nanosleep],

    [gl_cv_func_nanosleep],

    [

     AC_RUN_IFELSE(

       [AC_LANG_SOURCE([[

          #include <errno.h>

          #include <limits.h>

          #include <signal.h>

          #if HAVE_SYS_TIME_H

           #include <sys/time.h>

          #endif

          #include <time.h>

          #include <unistd.h>

          #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))

          #define TYPE_MAXIMUM(t) \

            ((t) (! TYPE_SIGNED (t) \

                  ? (t) -1 \

                  : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))

          static void

          check_for_SIGALRM (int sig)

          {

            if (sig != SIGALRM)

              _exit (1);

          }

          int

          main ()

          {

            static struct timespec ts_sleep;

            static struct timespec ts_remaining;

            static struct sigaction act;

            /* Test for major problems first.  */

            if (! nanosleep)

              return 2;

            act.sa_handler = check_for_SIGALRM;

            sigemptyset (&act.sa_mask);

            sigaction (SIGALRM, &act, NULL);

            ts_sleep.tv_sec = 0;

            ts_sleep.tv_nsec = 1;

            alarm (1);

            if (nanosleep (&ts_sleep, NULL) != 0)

              return 3;

            /* Test for a minor problem: the handling of large arguments.  */

            ts_sleep.tv_sec = TYPE_MAXIMUM (time_t);

            ts_sleep.tv_nsec = 999999999;

            alarm (1);

            if (nanosleep (&ts_sleep, &ts_remaining) != -1)

              return 4;

            if (errno != EINTR)

              return 5;

            if (ts_remaining.tv_sec <= TYPE_MAXIMUM (time_t) - 10)

              return 6;

            return 0;

          }]])],

       [gl_cv_func_nanosleep=yes],

       [case $? in dnl (

        4|5|6) gl_cv_func_nanosleep='no (mishandles large arguments)';; dnl (

        *)   gl_cv_func_nanosleep=no;;

        esac],

       [case "$host_os" in dnl ((

          linux*) # Guess it halfway works when the kernel is Linux.

            gl_cv_func_nanosleep='guessing no (mishandles large arguments)' ;;

          *)      # If we don't know, assume the worst.

            gl_cv_func_nanosleep='guessing no' ;;

        esac

       ])

    ])

   case "$gl_cv_func_nanosleep" in

     *yes)

       REPLACE_NANOSLEEP=0

       ;;

     *)

       REPLACE_NANOSLEEP=1

       case "$gl_cv_func_nanosleep" in

         *"mishandles large arguments"*)

           AC_DEFINE([HAVE_BUG_BIG_NANOSLEEP], [1],

             [Define to 1 if nanosleep mishandles large arguments.])

           ;;

         *)

           # The replacement uses select(). Add $LIBSOCKET to $LIB_NANOSLEEP.

           for ac_lib in $LIBSOCKET; do

             case " $LIB_NANOSLEEP " in

               *" $ac_lib "*) ;;

               *) LIB_NANOSLEEP="$LIB_NANOSLEEP $ac_lib";;

             esac

           done

           ;;

       esac

       ;;

   esac

 else

   HAVE_NANOSLEEP=0

 fi

 LIBS=$nanosleep_save_libs

])

# Prerequisites of lib/nanosleep.c.

AC_DEFUN([gl_PREREQ_NANOSLEEP],

[

  AC_CHECK_HEADERS_ONCE([sys/select.h])

  gl_PREREQ_SIG_HANDLER_H

])