www.pudn.com > mult_thread.rar > mutex.c

#include  
#include  
#include  
#include  
#include  
 
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; 
int lock_var; 
time_t end_time; 
 
void pthread1(void *arg); 
void pthread2(void *arg); 
 
int main(int argc, char *argv[]) 
{ 
	pthread_t id1,id2; 
	pthread_t mon_th_id; 
	int ret; 
 
	end_time = time(NULL)+10; 
	pthread_mutex_init(&mutex,NULL); 
	ret=pthread_create(&id1,NULL,(void *)pthread1, NULL); 
	if(ret!=0) 
		perror("pthread cread1"); 
	ret=pthread_create(&id2,NULL,(void *)pthread2, NULL); 
	if(ret!=0) 
		perror("pthread cread2"); 
	pthread_join(id1,NULL); 
	pthread_join(id2,NULL); 
	exit(0); 
} 
 
void pthread1(void *arg) 
{ 
	int i; 
	while(time(NULL) < end_time){ 
		if(pthread_mutex_lock(&mutex)!=0){ 
		perror("pthread_mutex_lock"); 
		} 
		else 
			printf("pthread1:pthread1 lock the variable\n"); 
		for(i=0;i<2;i++){ 
			sleep(1); 
			lock_var++; 
		} 
		if(pthread_mutex_unlock(&mutex)!=0){ 
			perror("pthread_mutex_unlock"); 
		} 
		else 
			printf("pthread1:pthread1 unlock the variable\n"); 
	sleep(1); 
	} 
} 
 
void pthread2(void *arg) 
{ 
	int nolock=0; 
	int ret; 
	while(time(NULL) < end_time){ 
		ret=pthread_mutex_trylock(&mutex); 
		if(ret==EBUSY) 
			printf("pthread2:the variable is locked by pthread1\n"); 
		else{ 
			if(ret!=0){ 
				perror("pthread_mutex_trylock"); 
				exit(1); 
			} 
			else 
				printf("pthread2:pthread2 got lock.The variable is %d\n",lock_var); 
			if(pthread_mutex_unlock(&mutex)!=0){ 
				perror("pthread_mutex_unlock"); 
			} 
			 else 
				printf("pthread2:pthread2 unlock the variable\n"); 
		} 
		sleep(3); 
	} 
}