From 9ef3a9f8b2704693496af12120ea3ab40389bf7b Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Mon, 24 Oct 2016 02:15:36 +0000
Subject:  Add the alarm library, first draft.

---
 src/libstddjb/alarm_milliseconds.c | 61 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 src/libstddjb/alarm_milliseconds.c

(limited to 'src/libstddjb/alarm_milliseconds.c')

diff --git a/src/libstddjb/alarm_milliseconds.c b/src/libstddjb/alarm_milliseconds.c
new file mode 100644
index 0000000..0628518
--- /dev/null
+++ b/src/libstddjb/alarm_milliseconds.c
@@ -0,0 +1,61 @@
+/* ISC license. */
+
+#include <skalibs/sysdeps.h>
+#include <skalibs/alarm.h>
+
+#ifdef SKALIBS_HASTIMER
+
+#include <errno.h>
+#include <signal.h>
+#include <time.h>
+#include "alarm-internal.h"
+
+#undef MYCLOCK
+#ifdef SKALIBS_HASCLOCKMON
+# define MYCLOCK CLOCK_MONOTONIC
+#else
+# define MYCLOCK CLOCK_REALTIME
+#endif
+
+int alarm_milliseconds (unsigned int t)
+{
+  struct itimerspec it = { .it_interval = { .tv_sec = 0, .tv_nsec = 0 }, .it_value = { .tv_sec = t / 1000, .tv_nsec = 1000000 * (t % 1000) } } ;
+  struct sigevent se = { .sigev_notify = SIGEV_SIGNAL, .sigev_signo = SIGALRM, .sigev_value = { .sival_int = 0 }, .sigev_notify_function = 0, .sigev_notify_attributes = 0 } ;
+  if (timer_create(MYCLOCK, &se, &timer_here) < 0) return 0 ;
+  if (timer_settime(timer_here, 0, &it, 0) < 0)
+  {
+    int e = errno ;
+    timer_delete(timer_here) ;
+    errno = e ;
+    return 0 ;
+  }
+  return 1 ;
+}
+
+#else
+#ifdef SKALIBS_HASITIMER
+
+#include <sys/time.h>
+
+int alarm_milliseconds (unsigned int t)
+{
+  struct itimerval it = { .it_interval = { .tv_sec = 0, .tv_usec = 0 }, .it_value = { .tv_sec = t / 1000, .tv_usec = 1000 * (t % 1000) } } ;
+  if (setitimer(ITIMER_REAL, &it, 0) < 0) return 0 ;
+  return 1 ;
+}
+
+#else
+
+#include <unistd.h>
+#include <limits.h>
+
+int alarm_milliseconds (unsigned int t)
+{
+  if (t > UINT_MAX - 999) return 0 ;
+  t = (t + 999) / 1000 ;
+  alarm(t) ;
+  return 1 ;
+}
+
+#endif
+#endif
-- 
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