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

#include  
#include  
#include  
#include  
#include  
#include  
#include  
int lock_var; 
time_t end_time; 
sem_t sem1,sem2; 
 
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)+30; 
	ret=sem_init(&sem1,0,1); 
	ret=sem_init(&sem2,0,0); 
	if(ret!=0) 
	{ 
		perror("sem_init"); 
	} 
	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){ 
		sem_wait(&sem2); 
		for(i=0;i<2;i++){ 
			sleep(1); 
			lock_var++; 
			printf("lock_var=%d\n",lock_var); 
		} 
		printf("pthread1:lock_var=%d\n",lock_var); 
		sem_post(&sem1); 
		sleep(1); 
	} 
} 
 
void pthread2(void *arg) 
{ 
	int nolock=0; 
	int ret; 
	while(time(NULL) < end_time){ 
	sem_wait(&sem1); 
	printf("pthread2:pthread1 got lock;lock_var=%d\n",lock_var); 
	sem_post(&sem2); 
	sleep(3); 
	} 
}