www.pudn.com > mult_thread.rar > exp1.c

#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#define FIFO "myfifo" 
#define N 5 
int lock_var; 
time_t end_time; 
char buf_r[100]; 
sem_t mutex,full,avail; 
int fd; 
void pthread1(void *arg); 
void pthread2(void *arg); 
void consumer(void *arg); 
void productor(void *arg); 
 
int main(int argc, char *argv[]) 
{ 
	pthread_t id1,id2; 
	pthread_t mon_th_id; 
	int ret; 
	end_time = time(NULL)+30; 
	if((mkfifo(FIFO,O_CREAT|O_EXCL)<0)&&(errno!=EEXIST)) 
		printf("cannot create fifoserver\n"); 
	printf("Preparing for reading bytes...\n"); 
	memset(buf_r,0,sizeof(buf_r)); 
	fd=open(FIFO,O_RDWR|O_NONBLOCK,0); 
	if(fd==-1) 
	{ 
		perror("open"); 
		exit(1); 
	} 
	ret=sem_init(&mutex,0,1); 
	ret=sem_init(&avail,0,N); 
	ret=sem_init(&full,0,0); 
	if(ret!=0) 
	{ 
		perror("sem_init"); 
	} 
	ret=pthread_create(&id1,NULL,(void *)productor, NULL); 
	if(ret!=0) 
		perror("pthread cread1"); 
	ret=pthread_create(&id2,NULL,(void *)consumer, NULL); 
	if(ret!=0) 
		perror("pthread cread2"); 
	pthread_join(id1,NULL); 
	pthread_join(id2,NULL); 
 
	exit(0); 
} 
 
void productor(void *arg) 
{ 
	int i,nwrite; 
	while(time(NULL) < end_time){ 
		sem_wait(&avail); 
		sem_wait(&mutex); 
		if((nwrite=write(fd,"hello",5))==-1) 
		{ 
			if(errno==EAGAIN) 
				printf("The FIFO has not been read yet.Please try later\n"); 
		} 
		else 
			printf("write hello to the FIFO\n"); 
		sem_post(&full); 
		sem_post(&mutex); 
		sleep(1); 
	} 
} 
 
void consumer(void *arg) 
{ 
	int nolock=0; 
	int ret,nread; 
	while(time(NULL) < end_time){ 
		sem_wait(&full); 
		sem_wait(&mutex); 
		memset(buf_r,0,sizeof(buf_r)); 
		if((nread=read(fd,buf_r,100))==-1){ 
			if(errno==EAGAIN) 
				printf("no data yet\n"); 
		} 
		printf("read %s from FIFO\n",buf_r); 
		sem_post(&avail); 
		sem_post(&mutex); 
		sleep(1); 
	} 
}