进程同步（一）—— 管道

#include <stdio.h> 
#include <string.h> 
#include <unistd.h> 
#include <iostream>

using namespace std;

const int MAX_BUFFSIZE = 1024;

int main() 
{ 
    int    pipe_fd[2]; 
    pid_t pid;  
    char buff[MAX_BUFFSIZE]; 
    
    memset(buff,'\0',sizeof(buff));
    
    if (pipe(pipe_fd) < 0) 
    {
          cout<<"pipe create error"; 
    }

    if ((pid = fork()) < 0) 
    {
        cout<<"fork error"; 
    }
    
    if (pid > 0)
    { 
        close(pipe_fd[0]);
        cin>>buff;
        write(pipe_fd[1],buff,sizeof(buff));
    } 
    if (pid == 0)
    { 
        close(pipe_fd[1]); 
        if ((read(pipe_fd[0],buff,MAX_BUFFSIZE)) > 0)
        {
            cout<<"Msg from parent:"<<buff;
        }
    } 
    return 0; 
}