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

char user[40];

//alarm 的捕捉函數(shù)
void catch_alarm(int sig_num)
{
	printf("Sorry, time limit reached.\n");
	//清除定時器
	alarm(0);
	exit(0);
}

int main(int argc, char* argv[])
{
	//設(shè)置信號回調(diào)
	signal(SIGALRM, catch_alarm);
	//提示輸入用戶名
	printf("Your Username(10 seconds limit): ");
	fflush(stdout);
	//設(shè)置10秒時限
	alarm(10);
	//等待用戶輸入
	(char *)gets(user);
	printf("Your username is: '%s'\n", user);
	return 0;
}