应用与MPlayer通过slave模式进行信息交换

应用与MPlayer通过slave模式进行信息交换

代码如下

编译方法

gcc test.c -lpthread

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

/**********************全局变量定义区*****************/
int fd_fifo;					//创建有名管道，用于向mplayer发送命令   
int fd_pipe[2];					//创建无名管道,用于从mplayer读取命令   
void *get_pthread (void *arg)
{

	char buf[100];
	while (1)
	{
		printf ("please input you cmd:");
		fflush (stdout);
		fgets (buf, sizeof (buf), stdin);	//从标准输入获取数据   
		buf[strlen (buf)] = '\0';
		printf ("*%s*\n", buf);
		if (write (fd_fifo, buf, strlen (buf)) != strlen (buf))
			perror ("write");	//将命令写入命名管道   
	}
}

void *print_pthread (void *arg)
{
	char buf[100];
	close (fd_pipe[1]);
	int size = 0;
	while (1)
	{
		size = read (fd_pipe[0], buf, sizeof (buf));	//从无名管道的写端读取信息打印在屏幕上   
		buf[size] = '\0';
		printf ("th msg read form pipe is %s\n", buf);
	}
}

int main (int argc, char *argv[])
{
	int fd;
	char buf[100];
	pid_t pid;
	unlink ("/tmp/my_fifo");	//如果明明管道存在，则先删除   
	mkfifo ("/tmp/my_fifo", O_CREAT | 0666);
	perror ("mkfifo");
	if (pipe (fd_pipe) < 0)		//创建无名管道   
	{
		perror ("pipe error\n");
		exit (-1);
	}
	pid = fork ();
	if (pid < 0)
	{
		perror ("fork");
	}
	if (pid == 0)				//子进程播放mplayer   
	{
		close (fd_pipe[0]);
		dup2 (fd_pipe[1], 1);	//将子进程的标准输出重定向到管道的写端   
		fd_fifo = open ("/tmp/my_fifo", O_RDWR);
		execlp ("mplayer", "mplayer", "-slave", "-quiet", "-loop", "0", "-input", "file=/tmp/my_fifo", "/home/user/Downloads/text2audio.mp3", NULL);
	}
	else
	{
		pthread_t tid1;
		pthread_t tid2;
		fd_fifo = open ("/tmp/my_fifo", O_RDWR);
		if (fd < 0)
			perror ("open");
		pthread_create (&tid1, NULL, get_pthread, NULL);	//从键盘获取控制信息   
		pthread_create (&tid2, NULL, print_pthread, NULL);	//打印从无名管道收到的信息   
		pthread_join (tid1, NULL);
		pthread_join (tid2, NULL);
	}
	return 0;
}