data_generate.c

一个编程中常用的PV操作(生产者—消费者)的c语言的demo

#include "outshm.h"

int main(void)
{
	struct exchange *shm,*s;
	int producer, consumer, i;
	char readbuf[[BUFSIZE];
	
	//creat and init consumer
	consumer = open_semaphore_set(ftok("consumer",0),1);
	init_a_semaphore(consumer,0,1);
	
	//creat and init producer
	producer = open_semaphore_set(ftok("producer",0),1);
	init_a_semaphore(producer,0,1);
	
	//get and connect the shm named"shared"
	shm = (struct exchange *)shminit(ftok("shared",0));
	
	//get data from input and put it to the shm
	for(i=0; ; i++)
	{
		//input
		printf("enter some test:");
		fgets(readbuf,BUFSIZE,stdin);
		int semaphore_P(consumer);//wait for the release of the shm
		
		//write shm buffer
		shm->seq = i;
		sprintf(shm->buf,""message %4d from producer %d is \"%s\"\n",i,getpid(),readbuf);
		semaphore_V(producer);
		if (strcmp(readbuf,"end",3) == 0)
			break;
	}
	exit(0);
}