Terminating app due to uncaught exception 'NSInternalInconsistencyException'

[johnhcc]

I'm running Mac OS 10.12.6. Building proceeds fine, but at runtime I'm getting the error Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'nextEventMatchingMask should only be called from the Main Thread!'.

Searching on this issue results in a lot of results, but not a lot of solutions, related to events/graphics calls being made outside the main thread.

Full error follows; thanks for any thoughts or ideas.

> ./snipes
2018-01-29 23:39:36.891 snipes[7435:42033] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'nextEventMatchingMask should only be called from the Main Thread!'
*** First throw call stack:
(
	0   CoreFoundation                      0x00007fff935632cb __exceptionPreprocess + 171
	1   libobjc.A.dylib                     0x00007fffa837a48d objc_exception_throw + 48
	2   AppKit                              0x00007fff9174ce82 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 4480
	3   libSDL2-2.0.0.dylib                 0x0000000109bc040c Cocoa_PumpEvents + 211
	4   libSDL2-2.0.0.dylib                 0x0000000109b5dca5 SDL_PumpEvents_REAL + 23
	5   libSDL2-2.0.0.dylib                 0x0000000109b5dd20 SDL_WaitEventTimeout_REAL + 76
	6   snipes                              0x0000000109ab1808 _ZL17ConsoleThreadFuncPv + 1112
	7   libSDL2-2.0.0.dylib                 0x0000000109b896f0 SDL_RunThread + 60
	8   libSDL2-2.0.0.dylib                 0x0000000109bc8b9b RunThread + 9
	9   libsystem_pthread.dylib             0x00007fffa8e7993b _pthread_body + 180
	10  libsystem_pthread.dylib             0x00007fffa8e79887 _pthread_body + 0
	11  libsystem_pthread.dylib             0x00007fffa8e7908d thread_start + 13
)
libc++abi.dylib: terminating with uncaught exception of type NSException
Abort trap: 6

[lifelike]

Get this same stack trace immediately on launch, also on 10.12.6. From what I can tell from various search results this has been solved in other projects by moving all rendering to the main thread? But it sounds more like a bug in this port of SDL2 than in Snipes itself, unless the SDL2 documentation says that you can only render things from the main thread?

[CyberShadow]

Well, ostensibly this port is only for Windows and Linux; the fact that the code compiles and almost runs on OS X is an emergent effect of trying to avoid platform-specific code where reasonable. I don't think either @Davidebyzero or I have an OS X machine, so... patches welcome :)

The reason the SDL port does rendering in a different thread is because that's kind of how things happened in the DOS version, where programs simply wrote stuff to the video buffer at A0000 / B8000, and the GPU (its own piece of hardware, but here "emulated" as a different thread) picked up and rendered stuff from there.

[johnhcc]

I don't think my C++ or SDL2 knowledge make it likely I will be able to fix this myself... but I will mess around with this for a while. I'm also more than happy to test any development branches if someone else feels like giving it a go.

As to what @lifelike wrote... this requirement that all rendering occur in the main thread is something MacOS started enforcing fairly recently (as revealed by a Google search of the error), and I don't know why they felt the need to step in and do this. I certainly understand why the rendering is done in a different thread in this case, given the historical nature of the software. It sounds like changing that is not a trivial task.

[CyberShadow]

If someone wants to have a go at this, the first thing I'd try is move the SDL_Init call from the OpenConsole function to inside the ConsoleThreadFunc function.