# serial 30

dnl From Jim Meyering.
dnl Check for the nanosleep function.
dnl If not found, use the supplied replacement.
dnl

# Copyright (C) 1999-2001, 2003-2010 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],
[
 dnl Persuade glibc and Solaris <time.h> to declare nanosleep.
 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])

 AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
 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])

 AC_REQUIRE([gl_MULTIARCH])
 if test $APPLE_UNIVERSAL_BUILD = 1; then
   # A universal build on Apple MacOS 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) 0 << (sizeof (t) * CHAR_BIT - 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;
          if (! nanosleep)
            return 1;
          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 1;
          ts_sleep.tv_sec = TYPE_MAXIMUM (time_t);
          ts_sleep.tv_nsec = 999999999;
          alarm (1);
          if (nanosleep (&ts_sleep, &ts_remaining) == -1 && errno == EINTR
              && TYPE_MAXIMUM (time_t) - 10 < ts_remaining.tv_sec)
            return 0;
          return 119;
        }]])],
     [gl_cv_func_nanosleep=yes],
     [case $? in dnl (
      119) gl_cv_func_nanosleep='no (mishandles large arguments)';; dnl (
      *)   gl_cv_func_nanosleep=no;;
      esac],
     [gl_cv_func_nanosleep=cross-compiling])
  ])
  if test "$gl_cv_func_nanosleep" = yes; then
    REPLACE_NANOSLEEP=0
  else
    REPLACE_NANOSLEEP=1
    if test "$gl_cv_func_nanosleep" = 'no (mishandles large arguments)'; then
      AC_DEFINE([HAVE_BUG_BIG_NANOSLEEP], [1],
        [Define to 1 if nanosleep mishandles large arguments.])
    else
      for ac_lib in $LIBSOCKET; do
        case " $LIB_NANOSLEEP " in
        *" $ac_lib "*) ;;
        *) LIB_NANOSLEEP="$LIB_NANOSLEEP $ac_lib";;
        esac
      done
    fi
    AC_LIBOBJ([nanosleep])
    gl_PREREQ_NANOSLEEP
  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
])