子进程的创建

父进程和子进程的生成

pid< 0 出错

pid==0 子进程

pid>0 父进程

#include<stdio.h>
#include<unistd.h>
#include<iostream>
using namespace std;

int main()
{

        pid_t pid;

        char *massage;
        pid = fork();

        if(pid<0)
        {

                cout<<"error"<<endl;



        }
        else if(pid ==0)
        {

                cout<<"This is a sonpid"<<endl;
                cout<<"sonpid=="<<getpid()<<endl;
                cout<<"fatherpid=="<<getppid()<<endl;

        }
        else
        {

                cout<<"This is a fatherpid"<<endl;

                cout<<"pid=="<<getpid()<<endl;
        }


        for(int i =0;i<4;i++)
        {

                cout<<getpid()<<endl;
                cout<<i<<endl;


        }

        return 0;
}

           

循环产生兄弟子进程；

#include<stdio.h>
#include<unistd.h>
#include<iostream>
using namespace std;

int main()
{

        pid_t pid;

        int number = 5;


        int i =0;
        for( i =0;i<number;i++)
        {

                pid = fork();
                if(pid ==0)
                {

                cout<<getpid()<<endl;
                   break;
                }



        }
        if(i==0)
        {
                cout<<getpid()<<endl;
        }
        return 0;
}