Linux 匿名管道

ゞ浴缸里的玫瑰 2022-07-20 12:06 139阅读 0赞

#include<stdio.h>
    #include<unistd.h>
    #include<sys/types.h>
    #include<sys/stat.h>
    #include<fcntl.h>
    #include<string.h>
    int main()
    {
    	int pipe_fd[2];
    	if (pipe(pipe_fd) < 0)//pipe函数用于创建管道，如果小于0，失败
    	{
    		perror("pipe\n");//perror打印错误信息
    		return 1;
    	}
    	pid_t id = fork();//创建子进程
    	if (id < 0)//<0表明出错返回
    	{
    		perror("fork\n");
    		return -1;
    	}
    	//子进程。创建子进程后，子进程返回0，父进程返回子进程id
    	else if (id == 0)
    	{
    		close(pipe_fd[0]);//child关闭读--向匿名管道中写入数据
    		const char* msg = "i am a child\n";
    		int count = 5;
    		int i = 0;
    		while (1)
    		{
    			write(pipe_fd[1], msg, strlen(msg));
    			if (count-- == 0)
    				break;
    
    			sleep(1);
    			printf("child: write data: %d\n", i++);
    		}
    		close(pipe_fd[1]);
    	}
    	else
    	{//父进程从匿名管道中读数据
    		close(pipe_fd[1]);//pipe_fd[1]为写数据--关闭写端
    		char buf[1024];
    		int count = 5;
    		while (1)
    		{
    			memset(buf, '\0', sizeof(buf));//每次进行初始化
    			ssize_t _s = read(pipe_fd[0], buf, sizeof(buf)-1);//读数据
    			if (_s > 0)//返回值大于0，读取成功，打印
    			{
    				printf("client ->server:%s\n", buf);
    			}
    			else if (_s == 0)//等于0，说明结束
    			{
    				printf("read pipe EOF...\n");
    			}
    			else//小于0 出错 直接退出循环
    				break;
    		}
    	}
    
    	close(pipe_fd[0]);
    	int status = 0;
    	pid_t ret = waitpid(id, &status, 0);//waitpid进程等待函数
    	if (ret == id)//ret==id 说明等待成功
    	{
    		printf("wait child sucess...\n");
    		printf("get sig:%d\n", status & 0xff);
    		printf("exit code :%d\n", (status >> 8) & 0xff);
    
    	}
    	return 0;
    }

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[Center]: /images/20220719/08a610f841b142148deaf4fe38a08f9b.png
[Center 1]: /images/20220719/de694a1721a14bca88230d52b360f4d1.png