Mark Callow
SDL_ShowMessageBox calls SDL_CaptureMouse which, in the UIKit driver, raises a “That operation is not supported” error, overwriting the SDL error that an application may be trying to report.
This is because UIKit SDL_CaptureMouse returns SDL_Unsupported() which ends up calling SDL_SetError() which has the following code:
/* If we are in debug mode, print out an error message */
SDL_LogDebug(SDL_LOG_CATEGORY_ERROR, "%s", SDL_GetError());
The SDL_GetError call here overwrites the static buffer…..
Although an application can avoid this by using SDL_GetErrorMsg(char* errstr, int maxlen) to avoid the static buffer, SDL should be fixed.
The fix is simple. In SDL_SetError change
SDL_LogDebug(SDL_LOG_CATEGORY_ERROR, "%s", SDL_GetError());
to
SDL_LogDebug(SDL_LOG_CATEGORY_ERROR, "%s", error);
where error is the pointer to the buffer where it assembled the message.
Amruth Raj
- My app runs in full screen to play video(I use SDL_WINDOW_FULLSCREEN_DESKTOP)
- Cmd-tab to go out of full screen to another app
- Cmd-tab again to get back to my app
- Press left mouse button at one of the edges of the screen, don't release yet.
After this point the main thread is stuck until I release the left mouse button and hence video rendering doesn't happen anymore.
On debugging more, I see that thread 0 is stuck as shown below with sendEvent processing left mouse down. It comes out only after it receives a left mouse up. There are some frames below which show NSWindowResizing, but my window flag doesn't have SDL_WINDOW_RESIZABLE set.
Thread 0:: CrBrowserMain Dispatch queue: com.apple.main-thread
0 libsystem_kernel.dylib 0x00007fffbe13d34a mach_msg_trap + 10
1 libsystem_kernel.dylib 0x00007fffbe13c797 mach_msg + 55
2 com.apple.CoreFoundation 0x00007fffa889d434 __CFRunLoopServiceMachPort + 212
3 com.apple.CoreFoundation 0x00007fffa889c8c1 __CFRunLoopRun + 1361
4 com.apple.CoreFoundation 0x00007fffa889c114 CFRunLoopRunSpecific + 420
5 com.apple.HIToolbox 0x00007fffa7dfdebc RunCurrentEventLoopInMode + 240
6 com.apple.HIToolbox 0x00007fffa7dfdcf1 ReceiveNextEventCommon + 432
7 com.apple.HIToolbox 0x00007fffa7dfdb26 _BlockUntilNextEventMatchingListInModeWithFilter + 71
8 com.apple.AppKit 0x00007fffa6396a54 _DPSNextEvent + 1120
9 com.apple.AppKit 0x00007fffa6b127ee -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 2796
10 com.apple.AppKit 0x00007fffa66f568d +[NSWindow(NSWindowResizing) _mouseHysteresisCheck:withExpiration:andDistance:finalMouseLocation:] + 525
11 com.apple.AppKit 0x00007fffa65eedb5 -[NSWindow(NSWindowResizing) _hitTestWithHysteresisCheck:forEvent:allowWindowDragging:] + 394
12 com.apple.AppKit 0x00007fffa6c8f0db -[NSWindow(NSEventRouting) _handleMouseDownEvent:isDelayedEvent:] + 1873
13 com.apple.AppKit 0x00007fffa6c8ca6c -[NSWindow(NSEventRouting) _reallySendEvent:isDelayedEvent:] + 1942
14 com.apple.AppKit 0x00007fffa6c8bf0a -[NSWindow(NSEventRouting) sendEvent:] + 541
15 org.libsdl.SDL2 0x000000010d46d74a -[SDLWindow sendEvent:] + 90
16 com.apple.AppKit 0x00007fffa6b10681 -[NSApplication(NSEvent) sendEvent:] + 1145
17 org.libsdl.SDL2 0x000000010d46532b -[SDLApplication sendEvent:] + 139
18 org.libsdl.SDL2 0x000000010d466b2f Cocoa_PumpEvents + 495
19 org.libsdl.SDL2 0x000000010d44c1d5 SDL_PumpEvents_REAL + 53
20 org.libsdl.SDL2 0x000000010d44c2f5 SDL_WaitEventTimeout_REAL + 53
21 org.libsdl.SDL2 0x000000010d44c2b7 SDL_PollEvent_REAL + 23
22 org.libsdl.SDL2 0x000000010d51bb24 SDL_PollEvent + 36
23 libTest.dylib 0x000000010cf3e0e8 SDLEventProcessor::processEvents(int) + 568
24 Test 0x000000010cde6bba BrowserApp::RunAppMessageLoop(BAInstData*, CefStringBase, CefStringBase) + 810
25 Test 0x000000010ce04bbc main + 17980
26 libdyld.dylib 0x00007fffbe016235 start + 1
I further noticed that while entering full screen in SDL_cocoawindow.m NSResizableWindowMask is set. If I clear it inside windowDidEnterFullScreen, then, the issue doesn't repro.
This is discussed at https://discourse.libsdl.org/t/main-thread-gets-stuck-on-left-mouse-down/22753/3 and thanks to Eric for the pointers.
The Xlib documentation demands that 32-bit values here be passed in a long,
even when long itself isn't a 32-bit value. Otherwise libx11 might read
memory incorrectly.
Fixes Bugzilla #3692.
Simon Hug
There's a chance that an audio conversion from many channels to a few can use more than 9 audio filters. SDL_AudioCVT has 10 SDL_AudioFilter pointers of which one has to be the terminating NULL pointer. The SDL code has no checks for this limit. If it overflows there can be stack or heap corruption or a call to 0xa.
Attached patch adds a function that checks for this limit and throws an error if it is reached. Also adds some documentation.
Test parameters that trigger this issue:
AUDIO_U16MSB with 224 channels at 46359 Hz
V
AUDIO_S16MSB with 6 channels at 27463 Hz
The fuzzer program I uploaded in bug 3667 has more of them.
This only affects Wayland and DirectFB, as a Unix system generally has X11
support. Other platforms also have different sizes for the C union in
question, but are likely the only target for that platform, etc.
Apps that might run on Wayland or DirectFB will need to be compiled against
new headers from an official 2.0.6 release, or be prepared to force the x11
target, or not use SDL_GetWindowWMInfo().
Fixes Bugzilla #3428.
