程序清单 8-8 exec函数实例，a.out是程序8-9产生的可执行程序

/*
 ============================================================================
 Name        : test.c
 Author      : blank
 Version     :
 Copyright   : Your copyright notice
 Description : 程序清单 8-8 exec函数实例，a.out是程序8-9产生的可执行程序============================================================================
*/

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

char *evn_init[] = { "USER=unknown", "PATH=/tmp", NULL};
int main(int argc, char *argv[])
{
    pid_t pid;

    if ((pid = fork()) < 0){
        err_sys("fork error");
    }else if (pid == 0){
        // specify pathname, specify environment
        if (execle("/home/blank/workspace/test/src/a.out", "a.out", "myarg1",
                "MY ARG2", (char *)0, evn_init) < 0){
            err_sys("execel error");
        }
    }

    if (waitpid(pid, NULL, 0) < 0){
        err_sys("waitpid error");
    }

    if ((pid = fork()) < 0){
        err_sys("fork error");
    }else if (pid == 0){
        // specify filename, inherit environment
        if (execlp("./a.out", "a.out", "only 1 arg", (char *)0) < 0){
            err_sys("execlp error");
        }
    }

    exit(0);
}