事件处理逻辑流程图

测试了libevent 事件处理(linux，Ctrl+C与kill)

#include <iostream>
#include <event2/event.h>
#ifndef _WIN32
#include <signal.h>
#endif // !_


using namespace std;

//sock文件描述符， which事件类型， arg传递的参数
static void Ctrl_C(int sock, short which, void* arg) {
	cout << "INPUT:>> Ctrl+C" << endl;
}

static void Kill(int sock, short which, void* arg) {
	cout << "INPUT:>> Kill" << endl;
	//如果处于非待决
	event* ev = (event*)arg;
	if (!evsignal_pending(ev, NULL))
	{
		event_del(ev);
		event_add(ev, NULL);
	}
}

int main(int argc, char** argv) {
#if _WIN32
	//windowns 初始化socket库
	WSADATA wsa;
	WSAStartup(MAKEWORD(2, 2), &wsa);
#else
	//linux 忽略管道信号，发送数据给已关闭的socket
	if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
		return 1;
#endif
	event_base* base = event_base_new();

#ifndef _WIN32
	//添加信号Ctrl+C 处于no_pending(隐藏的状态：EV_SIGNAL|EV_PERSIST)
	event* c_signal = evsignal_new(base, SIGINT, Ctrl_C, base);
	if (!c_signal){
		cerr << "SIGINT evsignal_new failed \n";
		return -1;
	}

	//添加事件到pending
	if (event_add(c_signal, 0) != 0) {
		cerr << "SIGINT event_add failed \n";
		return -1;
	}

	//添加kill信号 (非持久，一次性, event_self_cbarg传递当前event)
	event* k_signal = event_new(base, SIGTERM, EV_SIGNAL, Kill, event_self_cbarg());
	if (!k_signal) {
		cerr << "k_signal evsignal_new failed \n";
		return -1;
	}

	//添加事件到pending
	if (event_add(k_signal, 0) != 0) {
		cerr << "SIGINT k_signal failed \n";
		return -1;
	}

	//进入事件主循环
	event_base_dispatch(base);
	event_free(c_signal);
	event_base_free(base);
#endif // _WIN32
#ifdef _WIN32
	WSACleanup();
#endif // _WIN32
	return 0;
}

效果如下：