boost::corosio::tcp_server::join

Block until all accept loops complete.

Synopsis

Declared in <boost/corosio/tcp_server.hpp>

void
join();

Description

Blocks the calling thread until all accept coroutines launched by start have finished executing. This synchronizes the shutdown sequence, ensuring the server is fully stopped before restarting or destroying it.

Preconditions

Postconditions

All accept loops have completed. The server is in the stopped state and may be restarted via start.

Example (Correct Usage)

// main thread
srv.start();
ioc.run();      // Blocks until work completes
srv.join();     // Safe: called after ioc.run() returns

WARNING: Deadlock Scenarios

Calling join() from the wrong context causes deadlock:

// WRONG: calling join() from inside a worker coroutine
void run( launcher launch ) override
{
    launch( ex, [this]() -> capy::task<>
    {
        srv_.join();  // DEADLOCK: blocks the executor
        co_return;
    }());
}

// WRONG: calling join() while ioc.run() is still active
std::thread t( [&]{ ioc.run(); } );
srv.stop();
srv.join();  // DEADLOCK: ioc.run() still running in thread t

Thread Safety

May be called from any thread, but will deadlock if called from within the io_context event loop or from a worker coroutine.