102 lines
2.4 KiB
C
102 lines
2.4 KiB
C
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/* ex7
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*
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* Test case that illustrates a timed wait on a condition variable.
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*/
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#include <errno.h>
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#include <stdio.h>
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#include <string.h>
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#include <pthread.h>
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#include <sys/time.h>
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#include <unistd.h>
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#define usleep rt_thread_sleep
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/* Our event variable using a condition variable contruct. */
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typedef struct {
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pthread_mutex_t mutex;
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pthread_cond_t cond;
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int flag;
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} event_t;
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/* Global event to signal main thread the timeout of the child thread. */
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event_t main_event;
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static void *test_thread(void *ms_param) {
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int status = 0;
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event_t foo;
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struct timespec time;
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struct timeval now;
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long ms = (long) ms_param;
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/* initialize cond var */
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pthread_cond_init(&foo.cond, NULL);
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pthread_mutex_init(&foo.mutex, NULL);
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foo.flag = 0;
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/* set the time out value */
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printf("waiting %ld ms ...\n", ms);
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gettimeofday(&now, NULL);
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time.tv_sec = now.tv_sec + ms / 1000 + (now.tv_usec + (ms % 1000) * 1000)
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/ 1000000;
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time.tv_nsec = ((now.tv_usec + (ms % 1000) * 1000) % 1000000) * 1000;
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/* Just use this to test the time out. The cond var is never signaled. */
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pthread_mutex_lock(&foo.mutex);
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while (foo.flag == 0 && status != ETIMEDOUT) {
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status = pthread_cond_timedwait(&foo.cond, &foo.mutex, &time);
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}
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pthread_mutex_unlock(&foo.mutex);
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/* post the main event */
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pthread_mutex_lock(&main_event.mutex);
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main_event.flag = 1;
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pthread_cond_signal(&main_event.cond);
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pthread_mutex_unlock(&main_event.mutex);
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/* that's it, bye */
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return (void*) status;
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}
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int libc_ex7(void) {
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unsigned long count;
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setvbuf(stdout, NULL, _IONBF, 0);
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/* initialize main event cond var */
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pthread_cond_init(&main_event.cond, NULL);
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pthread_mutex_init(&main_event.mutex, NULL);
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main_event.flag = 0;
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for (count = 0; count < 20; ++count) {
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pthread_t thread;
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int status;
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/* pass down the milli-second timeout in the void* param */
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status = pthread_create(&thread, NULL, test_thread, (void*) (count
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* 100));
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if (status != 0) {
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printf("status = %d, count = %lu: %s\n", status, count, strerror(
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errno));
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return 1;
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} else {
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/* wait for the event posted by the child thread */
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pthread_mutex_lock(&main_event.mutex);
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while (main_event.flag == 0) {
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pthread_cond_wait(&main_event.cond, &main_event.mutex);
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}
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main_event.flag = 0;
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pthread_mutex_unlock(&main_event.mutex);
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printf("count = %lu\n", count);
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}
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usleep(10);
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}
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return 0;
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}
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#include <finsh.h>
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FINSH_FUNCTION_EXPORT(libc_ex7, example 7 for libc);
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