66 lines
1.6 KiB
C
66 lines
1.6 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <semaphore.h>
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#include <pthread.h>
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#include <time.h>
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#include <errno.h>
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#include <string.h>
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#include <unistd.h>
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void func(sem_t *semp)
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{
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struct timespec ts;
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sleep(2);
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ts.tv_sec = 0;
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ts.tv_nsec = -1;
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errno = 0;
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printf("thread: calling sem_timedwait with bogus tv_nsec\n");
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if (sem_timedwait(semp, &ts) != 0)
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printf("thread: sem_timedwait: errno = %d strerror = %s\n",
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errno, strerror(errno));
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printf("thread: calling sem_post\n");
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if (sem_post(semp) != 0)
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printf("thread: sem_post: errno = %d strerror = %s\n", errno,
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strerror(errno));
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}
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int main()
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{
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struct timespec ts;
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pthread_t thread;
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sem_t sem;
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int i = 0, sval = 0;
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sem_init(&sem, 0, 0);
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pthread_create(&thread, NULL, (void *)&func, (void *)&sem);
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/* two passes to illustrate that only the processes that are already
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waiting for the semaphore when the call to sem_timedwait with the
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bogus args is made are negatively impacted, i.e. subsequent calls
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to sem_timedwait succeed */
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for (i = 0; i < 2; i++) {
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sem_getvalue(&sem, &sval);
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printf("main: top of loop: sval = %d\n", sval);
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clock_gettime(CLOCK_REALTIME, &ts);
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ts.tv_sec += 10;
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ts.tv_nsec = 0;
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printf("main: calling sem_timedwait\n");
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if (sem_timedwait(&sem, &ts) != 0) {
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printf("main: sem_timedwait: errno = %d strerror = "
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"%s\n", errno, strerror(errno));
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} else {
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printf("main: sem_timedwait: success\n");
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printf("main: calling sem_post\n");
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if (sem_post(&sem) != 0)
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printf("thread: sem_post: errno = %d strerror "
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"= %s\n", errno, strerror(errno));
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}
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}
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}
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