子进程调用mpg123播放歌曲

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>

#define BUFSIZE	4096

int main(int argc, char *argv[]) {
	int fd, pipefd[2];
	pid_t pid;
	char buf[BUFSIZE];
	ssize_t ret;

	if(argc != 2)
	{
		fprintf(stderr, "Usage: %s <path_to_mp3_file>\n", argv[0]);
		exit(1);
	}

	fd = open(argv[1], O_RDONLY);
	if(fd == -1)
	{
		perror("open()");
		exit(1);
	}

	if(pipe(pipefd) == -1)
	{
		perror("pipe()");
		exit(1);
	}

	pid = fork();
	if(pid < 0)
	{
		perror("fork()");
		exit(1);
	} else if(pid == 0) {		// child process
		close(pipefd[1]);		// close the write end of the pipe
		dup2(pipefd[0], STDIN_FILENO);		// redirect stdin to read end of the pipe
		execlp("mpg123", "mpg123", "-", NULL);		// play from stdin ("-")
		perror("execlp()");		// only gets here if there's an error
		exit(1);
	} else {		// parent process
		close(pipefd[0]);		// close the read end of the pipe
		while((ret = read(fd, buf, BUFSIZE)) > 0) {
			write(pipefd[1], buf, ret);
		}
		close(pipefd[1]);
		close(fd);
		wait(NULL);		// wait for the child to finish
	}

	exit(0);
}