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-rw-r--r--test/pthread/ex7.c103
1 files changed, 103 insertions, 0 deletions
diff --git a/test/pthread/ex7.c b/test/pthread/ex7.c
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+/* ex7
+ *
+ * Test case that illustrates a timed wait on a condition variable.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <pthread.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+/* Our event variable using a condition variable contruct. */
+typedef struct {
+ pthread_mutex_t mutex;
+ pthread_cond_t cond;
+ int flag;
+} event_t;
+
+
+/* Global event to signal main thread the timeout of the child thread. */
+event_t main_event;
+
+
+void *
+test_thread (void *ms_param)
+{
+ int status = 0;
+ event_t foo;
+ struct timespec time;
+ struct timeval now;
+ long ms = (long) ms_param;
+
+ /* initialize cond var */
+ pthread_cond_init(&foo.cond, NULL);
+ pthread_mutex_init(&foo.mutex, NULL);
+ foo.flag = 0;
+
+ /* set the time out value */
+ printf("waiting %ld ms ...\n", ms);
+ gettimeofday(&now, NULL);
+ time.tv_sec = now.tv_sec + ms/1000 + (now.tv_usec + (ms%1000)*1000)/1000000;
+ time.tv_nsec = ((now.tv_usec + (ms%1000)*1000) % 1000000) * 1000;
+
+ /* Just use this to test the time out. The cond var is never signaled. */
+ pthread_mutex_lock(&foo.mutex);
+ while (foo.flag == 0 && status != ETIMEDOUT) {
+ status = pthread_cond_timedwait(&foo.cond, &foo.mutex, &time);
+ }
+ pthread_mutex_unlock(&foo.mutex);
+
+ /* post the main event */
+ pthread_mutex_lock(&main_event.mutex);
+ main_event.flag = 1;
+ pthread_cond_signal(&main_event.cond);
+ pthread_mutex_unlock(&main_event.mutex);
+
+ /* that's it, bye */
+ return (void*) status;
+}
+
+int
+main (void)
+{
+ unsigned long count;
+
+ setvbuf (stdout, NULL, _IONBF, 0);
+
+ /* initialize main event cond var */
+ pthread_cond_init(&main_event.cond, NULL);
+ pthread_mutex_init(&main_event.mutex, NULL);
+ main_event.flag = 0;
+
+ for (count = 0; count < 20; ++count)
+ {
+ pthread_t thread;
+ int status;
+
+ /* pass down the milli-second timeout in the void* param */
+ status = pthread_create (&thread, NULL, test_thread, (void*) (count*100));
+ if (status != 0) {
+ printf ("status = %d, count = %lu: %s\n", status, count,
+ strerror (errno));
+ return 1;
+ }
+ else {
+
+ /* wait for the event posted by the child thread */
+ pthread_mutex_lock(&main_event.mutex);
+ while (main_event.flag == 0) {
+ pthread_cond_wait(&main_event.cond, &main_event.mutex);
+ }
+ main_event.flag = 0;
+ pthread_mutex_unlock(&main_event.mutex);
+
+ printf ("count = %lu\n", count);
+ }
+
+ usleep (10);
+ }
+
+ return 0;
+}