+ 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