1 files changed, 40 insertions, 0 deletions
diff --git a/linux/timer.c b/linux/timer.c
new file mode 100644
index 0000000000..306db9c40b
--- /dev/null
+++ b/linux/timer.c
@@ -0,0 +1,40 @@
+/* POSIX compatible timer callback */
+#include <sys/time.h>
+#include <signal.h>
+#include <stddef.h>
+
+#include "timer.h"
+
+static timer_callback *user_func = NULL;
+static struct itimerval otimer;
+static void (*old_alrm)(int) = SIG_DFL;
+
+static void my_alarm_handler( int signo )
+{
+  if(user_func) (*user_func)();
+}
+
+unsigned set_timer_callback(unsigned ms,timer_callback func)
+{
+   unsigned ret;
+   struct itimerval itimer;
+   user_func = func;
+   getitimer(ITIMER_REAL,&otimer);
+   old_alrm = signal(SIGALRM,my_alarm_handler);
+   signal(SIGALRM,my_alarm_handler);
+   itimer.it_interval.tv_sec = 0;
+   itimer.it_interval.tv_usec = ms*1000;
+   itimer.it_value.tv_sec = 0;
+   itimer.it_value.tv_usec = ms*1000;
+   setitimer(ITIMER_REAL,&itimer,NULL);
+   getitimer(ITIMER_REAL,&itimer);
+   ret = itimer.it_interval.tv_sec*1000 + itimer.it_interval.tv_usec/1000;
+   if(!ret) restore_timer();
+   return ret;
+}
+
+void restore_timer(void)
+{
+  signal(SIGALRM,old_alrm);
+  setitimer(ITIMER_REAL,&otimer,NULL);
+}