Interruptbeispiel hinzugefügt (IRealTimer mittels manueller alarm() Nachstellung alle 1 Sekunde.

20160523/alarm-2.c

+#include <stdio.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+volatile sig_atomic_t keep_going = 1;
+struct timeval tv;
+int uOffset;
+
+void exitHandler(int sig)
+{
+  keep_going = 0;
+}
+
+void catchAlarm (int sig)
+{
+  if(keep_going)
+    alarm(10);
+  gettimeofday(&tv, NULL); //Get current time
+
+  printf("Hello World at %d seconds and %d microseconds! us between: %d microseconds!\n", 
+(int)tv.tv_sec, (int)tv.tv_usec, (int)tv.tv_usec - uOffset);
+  uOffset = (int)tv.tv_usec;
+}
+
+
+int main(void)
+{
+  keep_going = 1;
+  uOffset = 0;
+
+  signal(SIGINT, exitHandler);
+  signal(SIGALRM, catchAlarm);
+  alarm(10);
+  while(keep_going);
+}

20160523/alarm.c

+/*
+  ALARM alle 1 Sekunden mittels IRealTimers und manueller Aktivierung des Timers mittels alarm().
+  Nachteil gegenüber einmaligem Intervall Setup: einige µs gehen bei jedem "nachstellen" des Int.
+  in catchAlarm() verloren.
+ */
+
+#include <stdio.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+volatile sig_atomic_t keep_going = 1;
+struct timeval tv;
+int uOffset;
+
+void exitHandler(int sig)
+{
+  keep_going = 0;
+}
+
+void catchAlarm (int sig)
+{
+  if(keep_going)
+    alarm(1);
+  gettimeofday(&tv, NULL); //Get current time
+
+  printf("Hello World at %d seconds and %d microseconds! us between: %d microseconds!\n", 
+(int)tv.tv_sec, (int)tv.tv_usec, (int)tv.tv_usec - uOffset);
+  uOffset = (int)tv.tv_usec;
+}
+
+
+int main(void)
+{
+  keep_going = 1;
+  uOffset = 0;
+
+  signal(SIGINT, exitHandler);
+  signal(SIGALRM, catchAlarm);
+  alarm(1);
+  while(keep_going);
+}