linux c 程序 pipe 通信代碼分析

[root@luozhonghua 04]# cat ex04-3-pipe02.c

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/types.h>

int main(void){

   int result=-1;

   int fd[2],nbytes;

   pid_t pid;

   char string[]="hello,pipe";

   char readbuffer[80];

   int *write_fd = &fd[1];  //可寫

   int *read_fd = &fd[0];  //read

   result = pipe(fd);  //create pipe

   if(-1 == result){

     printf("create pipe faile");

     return -1;

    }

   pid=fork(); //分叉程式

   if(-1 == pid){

    printf("fork 程序失敗\n");

    return -1;

   }

   if(0 == pid ){

     close(*read_fd);

     /*向管道端寫入字元*/

     result=write(*write_fd,string,strlen(string));

   }else{

     close(*write_fd);

     /* read pipe data */

     nbytes=read(*read_fd,readbuffer,sizeof(readbuffer));

     printf("接收到%d 個資料，内容：%s \n",nbytes,readbuffer);

     printf("sizeof(readbuffer) =  %d\n",sizeof(readbuffer));

   return 0;

}

--------------測試結果

[root@luozhonghua 04]# ./ex04-3-pipe02

接收到10 個資料，内容：hello,pipe

sizeof(readbuffer) =  80