无名管道练习小程序

任务： 写一个程序，主程序向管道读数据，子进程向管道从终端设备上写数据。

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

int main(int argc, const char* argv[]){
    int pipe_id[2];
    pid_t child_pid;
    int return_val;
    char write_buff[1024];
    char read_buff[1024];
    int return_n_write;
    int return_n_read;
    /*1、创建管道*/
    return_val = pipe(pipe_id);
    /*1)判断管道是否创建成功*/
    if(return_val == -1){
        perror("pipe create\n");
        return -1;
    }
    
    child_pid = fork();
    if(child_pid == -1){
        perror("process create\n");
    }
    else if(child_pid == 0)
    {   
        /*子进程:写,关闭读端*/
        close(pipe_id[0]);
        while(1){/*子进程开始向管道写数据*/

            /*向标准输入中写入数据，写到缓冲区中*/
            fgets(write_buff,sizeof(write_buff),stdin);

            /*把写缓冲区的内容写到管道了里面*/
            return_n_write =  write(pipe_id[1],write_buff,1024);
           
            /*判断是否向管道写入成功*/
            if(return_n_write == -1){
                perror("write error\n");
                return -1;
            }
        }
    }
    else if((child_pid > 0))
    {
        /*主进程，读取管道内容*/
        close(pipe_id[1]);
        while(1)
        {
            return_n_read = read(pipe_id[0],read_buff,1024);
            if(return_n_read == -1){
                printf("read from write buff error\n");
                return -1;
            }
            /*从管道读数据成功，将读到的数据打印到终端设备上*/    
            printf("Read from pipe: %s\n",read_buff);
            
            if(!(strncmp(write_buff,"quit",4)))
                break;
        }

         /*判断输入的是不是quit,如果是的话，结束子进程*/

    }
    return 0;
}