unix高级编程8-8

#include"apue.h"
#include<sys/wait.h>

char *env_init[]={"USER=unknow","PATH=/tmp",NULL};

int main()
{
    pid_t pid;
    if((pid=fork())<0)
    {
        printf("fork1 error\n");
        exit(1);
    }
    else if(pid==0)
    {
        if(execle("/bin/ls","ls","-a",NULL,env_init)<0)
        {
            printf("execle error\n");
            fflush();
            exit(0);
        }
    }

    if(waitpid(pid,NULL,0)<0)
    {
        printf("wait error\n");
        exit(1);
    }


    if((pid=fork())<0)
    {
        printf("fork2 error\n");
        exit(1);
    }
    else if(pid==0)
    {
        if(execlp("ls","ls","-a",NULL)<0)
        {
            printf("execlp error\n");
            exit(1);
        }
    }

    exit(0);

}