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# Check for a working timer_create(). We need a pretty detailed check
# here, because there exist partially-working implementations of
# timer_create() in certain versions of Linux (see bug #1933).
#
AC_DEFUN([FP_CHECK_TIMER_CREATE],[
AC_CHECK_FUNC([timer_create],[HAVE_timer_create=yes],[HAVE_timer_create=no])
if test "$HAVE_timer_create" = "yes"
then
if test "$cross_compiling" = "yes"
then
# We can't test timer_create when we're cross-compiling, so we
# optimistiaclly assume that it actually works properly.
AC_DEFINE([USE_TIMER_CREATE], 1, [Define to 1 if we can use timer_create(CLOCK_REALTIME,...)])
else
AC_CACHE_CHECK([for a working timer_create(CLOCK_REALTIME)],
[fptools_cv_timer_create_works],
[AC_TRY_RUN([
#include <stdio.h>
#if defined(HAVE_STDLIB_H)
#include <stdlib.h>
#endif
#if defined(HAVE_TIME_H)
#include <time.h>
#endif
#if defined(HAVE_SIGNAL_H)
#include <signal.h>
#endif
#if defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif
static volatile int tock = 0;
static void handler(int i)
{
tock = 1;
}
static void timeout(int i)
{
// timer_settime() has been known to hang, so just in case
// we install a 1-second timeout (see #2257)
exit(99);
}
int main(int argc, char *argv[])
{
struct sigevent ev;
timer_t timer;
struct itimerspec it;
struct sigaction action;
int m,n,count = 0;
ev.sigev_notify = SIGEV_SIGNAL;
ev.sigev_signo = SIGVTALRM;
action.sa_handler = handler;
action.sa_flags = 0;
sigemptyset(&action.sa_mask);
if (sigaction(SIGVTALRM, &action, NULL) == -1) {
fprintf(stderr,"SIGVTALRM problem\n");
exit(3);
}
action.sa_handler = timeout;
action.sa_flags = 0;
sigemptyset(&action.sa_mask);
if (sigaction(SIGALRM, &action, NULL) == -1) {
fprintf(stderr,"SIGALRM problem\n");
exit(3);
}
alarm(1);
if (timer_create(CLOCK_REALTIME, &ev, &timer) != 0) {
fprintf(stderr,"No CLOCK_REALTIME timer\n");
exit(2);
}
tock = 0;
it.it_value.tv_sec = 0;
it.it_value.tv_nsec = 1000000; // 1ms
it.it_interval = it.it_value;
if (timer_settime(timer, 0, &it, NULL) != 0) {
fprintf(stderr,"settime problem\n");
exit(4);
}
// some environments have coarse scheduler/timer granularity of ~10ms and worse
usleep(100000); // 100ms
if (!tock) {
fprintf(stderr,"no CLOCK_REALTIME signal\n");
exit(5);
}
timer_delete(timer);
exit(0);
}
],
[fptools_cv_timer_create_works=yes],
[fptools_cv_timer_create_works=no])
])
case $fptools_cv_timer_create_works in
yes) AC_DEFINE([USE_TIMER_CREATE], 1,
[Define to 1 if we can use timer_create(CLOCK_REALTIME,...)]);;
esac
fi
fi
])
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