1 /** Hold several types of synchronization objects locked as long as specified. 2 */ 3 4 #define _GNU_SOURCE 1 5 6 #include <assert.h> 7 #include <pthread.h> 8 #include <stdio.h> 9 #include <stdlib.h> 10 #include <time.h> 11 #include <unistd.h> 12 13 14 static void delay_ms(const int ms) 15 { 16 struct timespec ts; 17 18 assert(ms >= 0); 19 ts.tv_sec = ms / 1000; 20 ts.tv_nsec = (ms % 1000) * 1000 * 1000; 21 nanosleep(&ts, 0); 22 } 23 24 int main(int argc, char** argv) 25 { 26 int interval = 0; 27 int optchar; 28 pthread_mutex_t mutex; 29 pthread_mutexattr_t mutexattr; 30 pthread_rwlock_t rwlock; 31 32 while ((optchar = getopt(argc, argv, "i:")) != EOF) 33 { 34 switch (optchar) 35 { 36 case 'i': 37 interval = atoi(optarg); 38 break; 39 default: 40 fprintf(stderr, "Usage: %s [-i <interval time in ms>].\n", argv[0]); 41 break; 42 } 43 } 44 45 fprintf(stderr, "Locking mutex ...\n"); 46 47 pthread_mutexattr_init(&mutexattr); 48 pthread_mutexattr_settype(&mutexattr, PTHREAD_MUTEX_RECURSIVE); 49 pthread_mutex_init(&mutex, &mutexattr); 50 pthread_mutexattr_destroy(&mutexattr); 51 pthread_mutex_lock(&mutex); 52 delay_ms(interval); 53 pthread_mutex_lock(&mutex); 54 pthread_mutex_unlock(&mutex); 55 pthread_mutex_unlock(&mutex); 56 pthread_mutex_destroy(&mutex); 57 58 fprintf(stderr, "Locking rwlock exclusively ...\n"); 59 60 pthread_rwlock_init(&rwlock, 0); 61 pthread_rwlock_wrlock(&rwlock); 62 delay_ms(interval); 63 pthread_rwlock_unlock(&rwlock); 64 pthread_rwlock_destroy(&rwlock); 65 66 fprintf(stderr, "Locking rwlock shared ...\n"); 67 68 pthread_rwlock_init(&rwlock, 0); 69 pthread_rwlock_rdlock(&rwlock); 70 delay_ms(interval); 71 pthread_rwlock_rdlock(&rwlock); 72 pthread_rwlock_unlock(&rwlock); 73 pthread_rwlock_unlock(&rwlock); 74 pthread_rwlock_destroy(&rwlock); 75 76 fprintf(stderr, "Done.\n"); 77 78 return 0; 79 } 80
