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/** Hold several types of synchronization objects locked as long as specified.
*/
#define _GNU_SOURCE 1
#include <assert.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
static void delay_ms(const int ms)
{
struct timespec ts;
assert(ms >= 0);
ts.tv_sec = ms / 1000;
ts.tv_nsec = (ms % 1000) * 1000 * 1000;
nanosleep(&ts, 0);
}
int main(int argc, char** argv)
{
int interval = 0;
int optchar;
pthread_mutex_t mutex;
pthread_mutexattr_t mutexattr;
pthread_rwlock_t rwlock;
while ((optchar = getopt(argc, argv, "i:")) != EOF)
{
switch (optchar)
{
case 'i':
interval = atoi(optarg);
break;
default:
fprintf(stderr, "Usage: %s [-i <interval time in ms>].\n", argv[0]);
break;
}
}
fprintf(stderr, "Locking mutex ...\n");
pthread_mutexattr_init(&mutexattr);
pthread_mutexattr_settype(&mutexattr, PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(&mutex, &mutexattr);
pthread_mutexattr_destroy(&mutexattr);
pthread_mutex_lock(&mutex);
delay_ms(interval);
pthread_mutex_lock(&mutex);
pthread_mutex_unlock(&mutex);
pthread_mutex_unlock(&mutex);
pthread_mutex_destroy(&mutex);
fprintf(stderr, "Locking rwlock exclusively ...\n");
pthread_rwlock_init(&rwlock, 0);
pthread_rwlock_wrlock(&rwlock);
delay_ms(interval);
pthread_rwlock_unlock(&rwlock);
pthread_rwlock_destroy(&rwlock);
fprintf(stderr, "Locking rwlock shared ...\n");
pthread_rwlock_init(&rwlock, 0);
pthread_rwlock_rdlock(&rwlock);
delay_ms(interval);
pthread_rwlock_rdlock(&rwlock);
pthread_rwlock_unlock(&rwlock);
pthread_rwlock_unlock(&rwlock);
pthread_rwlock_destroy(&rwlock);
fprintf(stderr, "Done.\n");
return 0;
}
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