When calling the app.run() method in the main function, it blocks the thread as expected. However, when running it in a thread, it doesn't block, which causes the HTTP service to fail.

[LetAmericaGreatAgain]

When calling the app.run() method in the main function, it blocks the thread as expected. However, when running it in a thread, it doesn't block, which causes the HTTP service to fail.

std::thread daemon([this]() {
        this->app->run();
    });
    daemon.join();

[Jacob-Burckhardt]

Your code mentions the app variable. You create app on one thread and you pass it to another thread via the lambda capture. Instead, try creating app in the daemon thread.

[uNetworkingAB]

It doesn't block because there is nothing to run. When you call run in another thread, it will use that thread's loop. But you have registered stuff in the main thread's loop.

run() uses thread local Loop. So you are trying to run another loop. You need to register stuff on the same thread that runs the app. Or, simply, you just need to stop using threads, since the library is single-threaded (with exceptions)