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Diffstat (limited to 'test/pthread/ex7.c')
-rw-r--r-- | test/pthread/ex7.c | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/test/pthread/ex7.c b/test/pthread/ex7.c new file mode 100644 index 000000000..fadaccaa1 --- /dev/null +++ b/test/pthread/ex7.c @@ -0,0 +1,103 @@ +/* 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; +} |