施用alarm和setjmp实现超时控制

使用alarm和setjmp实现超时控制

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <setjmp.h>

#define JMP_VALUE 12345

static jmp_buf test_jmp_env;

static void test_alarm(int n)
{
	printf("alarm signal:%d\r\n", n);
    longjmp(test_jmp_env, JMP_VALUE);
}

void DoSomething()
{
	int i = 0;
	while(1){
		printf("%d\r\n", i++);
		sleep(1);
	}
}

void DoSomethingWithTimeout(int nTimeout)
{
	__sighandler_t old_handler = signal(SIGALRM, test_alarm);

	alarm(nTimeout);

	int n = setjmp(test_jmp_env);
	printf("setjmp result:%d\r\n", n);

	if(JMP_VALUE == n){
		signal(SIGALRM, old_handler);
		return;
	}
	else if(0 == n)
	{
		DoSomething();
		alarm(0);
		signal(SIGALRM, old_handler);
	}
	else
	{
		printf("error\r\n");
		exit(-1);
	}
}

int main(void)
{
	DoSomethingWithTimeout(5);

	printf("go on to do...\r\n");

	return 0;
}