如何打破libevent的调度循环 [英] How to break out libevent's dispatch loop
问题描述
我在一个单独的线程中使用nice libevent库实现了一个小的web服务器。 Web服务器运行event_base_dispatch（）以处理所有事件。我需要的是一种方法来打破这个调度循环从主线程。
I've implemented a tiny webserver in a separate thread using the nice libevent library. The webserver runs event_base_dispatch() to process all events. What I need is a way to break out this dispatch loop from the main thread.
它可以归结为以下C ++代码：
It boils down to the following C++ code:
#include <stdlib.h>
#include <signal.h>
#include <thread>
#include <evhttp.h>
struct event_base *eb;
std::thread t;
static volatile sig_atomic_t bailout = false;
void my_signal_handler(int) {
bailout = true;
}
void onRequest(evhttp_request *req, void *) {
struct evbuffer *OutBuf = evhttp_request_get_output_buffer(req);
evbuffer_add_printf(OutBuf, "<html><body>Testing 1-2-3</body></html>");
evhttp_send_reply(req, HTTP_OK, "OK", OutBuf);
}
void dispatch() {
eb = event_base_new();
struct evhttp *http = evhttp_new(eb);
evhttp_set_gencb(http, &onRequest, NULL);
evhttp_bind_socket_with_handle(http, "0.0.0.0", 5555);
event_base_dispatch(eb);
}
int main() {
struct sigaction sigIntHandler;
sigIntHandler.sa_handler = my_signal_handler;
sigemptyset(&sigIntHandler.sa_mask);
sigIntHandler.sa_flags = 0;
sigaction(SIGINT, &sigIntHandler, NULL);
t = std::thread { &dispatch };
while ( ! bailout ) {
std::this_thread::sleep_for(std::chrono::seconds(1));
}
event_base_loopexit(eb, NULL);
t.join();
}
行为是，如果您运行程序，请求页面，程序通过Ctrl-C，event_base_dispatch（）继续运行，直到您获取另一个网页。
The behavior is that if you run the program, request a page, abort the program by Ctrl-C, the event_base_dispatch() keeps running until you fetch another web page. Only then the loop aborts and the program terminates.
推荐答案
如果需要在运行任何更多回调之前退出事件循环，请使用event_base_break（）
If you need the event loop to exit before running any more callbacks, use event_base_break()
http://www.wangafu.net/~nickm/libevent-book/Ref3_eventloop.html
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