Dwarf Fortress hangs when quitting while a client is connected to DFHack server

[cvuchener]

I fell into a rabbit hole.

My understanding is that the detached connection thread blocks in recv. When the client finally tries to send something, the thread is unblocked and will terminate because of an error or BlockGuard throwing.

Solving this would require a way to wake up the connection threads when quitting, but I don't find such mechanism in clsocket.

[cvuchener]

I have several ideas, none seems simple:

• Using SimpleSocket::Close to interrupt the connection thread. Not very clean and SimpleSocket::Close is not thread-safe because of the internal buffer and error handling. Making it thread-safe will likely require an API change.
• Make (NotSo)SimpleSocket interruptible. This will require API changes too. I may be able to do it for Windows and Linux, but not for macOS.
• Replace clsocket with another library. I don't have suggestions to make. My experience is limited to pure POSIX socket or Qt's (but it is a big framework so not a good idea here).

What is the scope of clsocket? I see it used in RemoteServer/RemoteClient and the luasocket plugin. Is it used outside of this repository?