pipe_readwrite.c

关于进程间通信的代码集锦

#include <unistd.h>
#include <sys/types.h>
#include <errno.h>

int main()
{
	int pipe_fd[2];
	pid_t pid;
	char r_buf[100];
	char w_buf[4];
	char* p_wbuf;
	int r_num;
	int cmd;
	
	memset(r_buf,0,sizeof(r_buf));
	memset(w_buf,0,sizeof(w_buf));
	p_wbuf=w_buf;
	if(pipe(pipe_fd)<0)
	{
		printf("pipe create error\n");
		return -1;
	}

	if((pid=fork())==0)
	{
		printf("In child process\n");
		close(pipe_fd[1]);
		//sleep(2);//
		r_num=read(pipe_fd[0],r_buf,100);
		if(r_num>0)
		{
			printf("read num is %d\n the data read from the pipe is %d\n",r_num,atoi(r_buf));		
		}
		else
		{
			printf("parent hasn't write yet\n");
		}
		close(pipe_fd[0]);
		exit(0);		
	}
	else if(pid>0)
	{
		printf("In parent process\n");
		close(pipe_fd[0]);
		strcpy(w_buf,"111");
		if(write(pipe_fd[1],w_buf,4)!=-1)
		{
			printf("parent write over\n");
		}
		close(pipe_fd[1]);
		printf("parent close fd[1] over\n");
		sleep(1);
//		waitpid(pid,NULL,0);
//		exit(0);
	}
	
	return 0;
}