多进程，父子进程

 

#include<stdio.h>
#include<unistd.h>
int main()
{
    pid_t cpid;
    int i=0;
    //父进程创建四个子进程
    for(;i<4;i++)
    {
        cpid=fork();
        if(cpid==0)
            break;
        else if(cpid<0)
        {

            printf("fork is error!");
            break;   
        }
    }

    if(cpid==0)
    {
        sleep(i);
        printf(" i am child ,my ID is %d",getpid());
    
    }
    else if(cpid>0)//父进程此时i为5
    {
        sleep(i);
        printf("i am parent,my ID is %d",getpid());
    }
    //证明了每个进程有不同的资源
    printf("  i==%d\n",i);
    return 0;
}

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 程序结果：