#include <sys/types.h>#include <sys/sem.h>#include <sys/ipc.h>#include <unistd.h>#include <stdlib.h>#include <sys/stat.h>#include <fcntl.h>#include <stdio.h>#include "sem_func.h"#define FILE_NAME "buffer"int file_creat;void write_data_base(){	int number;	int fd;	int n;	srand(time(0));	number = rand()%100;	printf("writer:%d	%d\n",getpid(),number);	if(file_creat == 0) {		if((fd = open(FILE_NAME,O_CREAT | O_RDWR | O_EXCL,S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)) < 0) {			if((fd = open(FILE_NAME,O_RDWR)) < 0) {				perror("open file fail\n");				exit(1);			}		}		file_creat = 1;	} else {		if((fd = open(FILE_NAME,O_RDWR)) < 0) {			perror("open file fail\n");			exit(1);		}	}	if((n = write(fd,&number,sizeof(int)) < sizeof(int))) {		perror("write error\n");		exit(1);	}	close(fd);	srand(time(0));	sleep(rand()%10+1);}int main(){	int semid_rc,semid_mutex,semid_db;	init(&semid_rc,0,LOCKFILE_RC);	init(&semid_db,1,LOCKFILE_DB);	init(&semid_mutex,1,LOCKFILE_MUTEX);	while(1) {		V(&semid_db);		/*do work*/		write_data_base();		P(&semid_db);	}	return 0;}