Linux C学习笔记07--管道通信

#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>

int main(int argc,char* argv[])
{
    int fprcw[2];            //for parent read,child write
    int fpwcr[2];
    char str[256];

    pid_t pid;

    if(pipe(fprcw) == -1)
    {
        perror("pipe1");
        return -1;
    }
    if(pipe(fpwcr) == -1)
    {
        perror("pipe2");
        close(fprcw[0]);
        close(fpwcr[0]);
        return -1;
    }
    
    pid = fork();
    if(pid == 0)
    {        
        close(fprcw[0]);
        close(fpwcr[1]);
        sleep(1);
        write(fprcw[1],"hello world!",12);
        read(fpwcr[0],str,256);
        printf("child str is:%s\n",str);

        close(fpwcr[0]);
        close(fprcw[1]);
    }
    else if(pid > 0) 
    {
        close(fpwcr[0]);
        close(fprcw[1]);
        write(fpwcr[1],"how are you!",12);
        
        if(waitpid(pid,NULL,0) == -1)
        {
            perror("waitpid");
        }
        read(fprcw[0],str,256);
        printf("parent str is: %s\n",str);
        close(fpwcr[1]);
        close(fprcw[0]);

    }
    else
    {
        perror("fork");

    }

    return 0;
}