/*fork.c*/
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
	pid_t result;
/*調用fork函數，其返回值為result*/
	result = fork();
/*通過result的值來判斷fork函數的返回情況，首先進行出錯處理*/
	if(result == -1){
		perror("fork");
		exit;
	}
/*返回值為0代表子進程*/
	else if(result == 0){
	printf("The return value is %d\nIn child process!!\nMy PID is %d\n",result,getpid());
}
/*返回值大于0代表父進程*/
	else 
	{
	printf("The return value is %d\nIn father process!!\nMy PID is %d\n",result,getpid());
	}
}