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The Mac build of my (mainly POSIX) application spawns a child thread that calls CFRunLoopRun() to do an event loop (to get network configuration change events from MacOS).
When it's time to pack things up and go away, the main thread calls CFRunLoopStop() on the child thread's run-loop, at which point CFRunLoopRun() returns in the child thread, the child thread exits, and the main thread (which was blocking waiting for the child thread to exit) can continue.
This appears to work, but my question is: is this a safe/recommended way to do it? In particular, is calling CFRunLoopStop() from another thread liable to cause a race condition? Apple's documentation is silent on the subject, as far as I can tell.
If calling CFRunLoopStop() from the main thread is not the solution, what is a good solution? I know I could have the child thread call CFRunLoopRunInMode() and wake up every so often to check a boolean or something, but I'd prefer not to have the child thread do any polling if I can avoid it.
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A CFRunLoop object monitors sources of input to a task and dispatches control when they become ready for processing. Examples of input sources might include user input devices, network connections, periodic or time-delayed events, and asynchronous callbacks.
A run loop mode is a collection of input sources and timers to be monitored and a collection of run loop observers to be notified. Each time you run your run loop, you specify (either explicitly or implicitly) a particular “mode” in which to run.
In the case of CFRunLoopStop - if it could only be called safely on the current run loop, then it would not be necessary to pass it a parameter indicating which run loop to stop.
The presence of the parameter is a strong indication that its ok to use it to stop run loops other than the current run loop.
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