#include<unistd.h>
#include<sys/types.h>
#include<iostream>
#include<string.h>
int main(int argc,char* argv[])
{
    int command_pipe[2];
    pid_t pid;
    pid = fork();
    char command_string[255];
    if(pipe(command_pipe) < 0)
        std::cerr<<"pipe failed"<<std::endl;
    if(pid<0)
        std::cerr<<"fork failed!"<<std::endl;
    if(pid == 0)
    {
        char ch[255] = {'\0'};
        close(command_pipe[1]);
        int n=read(command_pipe[0],ch,255);
        std::cout<<"child read:"<<n<<std::endl;
        std::cout<<ch<<std::endl;

    }
    else
        if(pid >0)
        {
            close(command_pipe[0]);
            char m[255];
            strcpy(m,"111");
            if(-1!= write(command_pipe[1],m,4))
                std::cout<<"write success"<<std::endl;
                        else
                                 std::cout<<"write fail"<<std::endl;
            close(command_pipe[1]);
        }
    return 0;
}