fifo1.c

《Linux程序设计权威指南》源代码

	/* File: fifo1.c */
	#include <unistd.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <string.h>
	#include <fcntl.h>
	#include <limits.h>
	#include <sys/types.h>
	#include <sys/stat.h>

	#define FIFO_NAME "/tmp/myfifo"
	#define BUFFER_SIZE PIPE_BUF
	#define TEN_MEG (1024 * 1024 * 10)

	int main(int argc, char *argv[])
	{
		int pipe_fd;
		int res;
		int open_mode = O_WRONLY;
		int bytes_sent = 0;
		char buffer[BUFFER_SIZE + 1];

		//判断FIFO是否存在, 如果不存在则建立
		if (access(FIFO_NAME, F_OK) == -1) {
			res = mkfifo(FIFO_NAME, 0777);
			if (res != 0) {
				fprintf(stderr, "Could not create fifo %s\n",
					FIFO_NAME);
				exit(1);
			}
		}

		//打开FIFO
		printf("Process %d opening FIFO O_WRONLY\n", getpid());
		pipe_fd = open(FIFO_NAME, open_mode);
		printf("Process %d result %d\n", getpid(), pipe_fd);

		if (pipe_fd != -1) {
			//发送数据
			while(bytes_sent < TEN_MEG) {
				res = write(pipe_fd, buffer, BUFFER_SIZE);
				if (res == -1) {
					fprintf(stderr,"Write error on pipe\n");
					exit(1);
				}
				bytes_sent += res;
			}
			close(pipe_fd); 
		} else {
			exit(1);
		}

		printf("Process %d finished\n", getpid());
		return 0;
	}