undefined reference to 'main'

2019独角兽企业重金招聘Python工程师标准>>>

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

int main()
{
  pid_t pid;
  pid = fork();
  switch(pid)
  {
    case 0:
    printf("child process is running, curpid is %d, parentpid is %d\n", pid, getpid());
    break;
    case -1:
    perror("process creation failed\n");
    break;
    default:
    printf("parent process is running, cur pid is %d, parentpid is %d\n", pid, getpid());
    break;
  }
  exit(0);
}

第一次编译出了个问题：undefined reference to main。在这之前我装了个g++，其他的没变，这个问题后来自己就好了，我也不知道为什么，有知道的帮忙解答下，先谢过了。

http://www.oschina.net/code/snippet_171680_6746

转载于:https://my.oschina.net/u/212651/blog/38450