我对 execl 的学习

上例子  [作者：技术者高健@博客园  mail: luckyjackgao@gmail.com ]

[root@localhost test]# cat exem.c
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

int main()
{
        pid_t mpid;
        
        mpid=fork();
       
       if( mpid<0)
       {

       }
       else if (mpid==0) { //the child itself
           
                if(execl("/soft/test/gaochange.o","gaochange",NULL)<0)
                        perror("execl error!");
                
                for (;;)
                {
                   fprintf(stderr,"after execl call\n");
                   sleep(5);
                }

       }else{
                for (;;)
                {
                   sleep(1);
                }                  
       }
}

被子进程调用起来的代码：

[root@localhost test]# cat gaochange.c
#include <stdio.h>

int main(int argc, char *argv[])
{

   for (;;)
   {
     sleep(10);
     fprintf(stderr,"we are in gaochange\n");     
   }

   return 0;
}
[root@localhost test]# 

运行的结果，是这样的：

[root@localhost test]# gcc -o gaochange.o gaochange.c
[root@localhost test]# gcc -o exem.o exem.c
[root@localhost test]# ./exem.o
we are in gaochange
we are in gaochange
we are in gaochange
we are in gaochange
we are in gaochange
we are in gaochange
we are in gaochange
we are in gaochange
we are in gaochange
we are in gaochange
we are in gaochange
we are in gaochange
we are in gaochange
….


[root@localhost test]# ps -ef|grep exem
root      3173  2957  0 09:10 pts/2    00:00:00 ./exem.o
root      3176  2917  0 09:10 pts/1    00:00:00 grep exem
[root@localhost test]# ps -ef|grep 3173
root      3173  2957  0 09:10 pts/2    00:00:00 ./exem.o
root      3174  3173  0 09:10 pts/2    00:00:00 gaochange
root      3179  2917  0 09:10 pts/1    00:00:00 grep 3173
[root@localhost test]# 

结束 [作者：技术者高健@博客园  mail: luckyjackgao@gmail.com ]