exit函數思索

1 exit 對比 return

exit 被 main 函數或者其他函數調用，都會結束程序

return 被 main 函數調用才會結束程式，但是其他函數調用不會

1 #include<stdio.h>
  2 #include<stdlib.h>
  3 int fun()
  4 {
  5 // exit(0);
  6    return 0;
  7 }
  8 int main()
  9 {
 10         printf("111\n");
 11         printf("222\n");
 12         fun();
 13         printf("333\n");
 14         printf("4444\n");
 15 }      

[email protected]:~/work$ ./a.out
111
222
[email protected]:~/work$ gcc test_exit.c 
[email protected]:~/work$ ./a.out
111
222
333
4444      

1 /* 
  2  *  fork_test.c 
  3  *  version 1 
  4  *  Created on: 2010-5-29 
  5  *      Author: wangth 
  6  */
  7 #include <unistd.h>
  8 #include <stdio.h>
  9 #include <stdlib.h>
 10 int main ()
 11 {   
 12     pid_t fpid; //fpid表示fork函數傳回的值  
 13     int count=0;
 14     fpid=fork(); 
 15     if (fpid < 0)   
 16         printf("error in fork!");
 17     else if (fpid == 0) {  
 18         printf("i am the child process, my process id is %d\n",getpid());
 19         exit(0);
 20         printf("我是爹的兒子\n");//對某些人來說中文看着更直白。  
 21         count++;
 22     }  
 23     else {
 24         while(1)
 25         {       
 26                 sleep(2);    
 27                 printf("i am the parent process, my process id is %d\n",getpid());
 28                 printf("我是孩子他爹\n");
 29                 count++;
 30         }
 31     }  
 32     printf("統計結果是: %d\n",count);
 33     return 0;
 34 }