SDL2 & GDB: program received signal ?, unknown signal

Question

Let's start with description what's happening: I'm playing with SDL2 library on Windows. I can compile programs using it, and when I run the .exe it works just fine. Problems arise when I try to debug it using GDB - when code comes to the SDL_Init or the SDL_OpenAudio functions (which possibly create new threads), GDB stops, shows "program received signal ?, unknown signal" message, and when I resume execution the program crashes. Apparently there is a bug in GDB (https://www.mail-archive.com/cygwin@cygwin.com/msg149735.html) related to a thread naming, and it should be fixed in GDB version 7.11.1-1. At first I was using GCC 5.1.0 (TDM) with GDB 7.6.1, so i decided to update to newer version. It looks that TDM doesn't provide any updates since about two years ago, so I installed MinGW-w64 (I don't remember now, but it might've been version 7.11 of GDB). Didn't help, GDB stil crashes. Next I searched for newer version of GDB, and found 7.12 (www dot equation dot com/servlet/equation.cm…

Accepted Answer

Ok, I think I found two ways of dealing with this. Source of problem lies in how GDB handles (or at least is supposed to handle) thread naming. To name a thread, one must raise exception with specific attributes. SDL2 does this in SDL_SYS_SetupThread function located in SDL2-2.0.5/src/thread/windows/SDL_systhread.c:168:

```
RaiseException(0x406D1388, 0, sizeof(inf) / sizeof(ULONG), (const ULONG_PTR*) &inf);
```

First option is to comment this line and recompile the library (well, compiling it is a problem in itself). Second option is to add:

```
SDL_SetHint(SDL_HINT_WINDOWS_DISABLE_THREAD_NAMING, "1");
```

somewhere early in code - in SDL_SYS_SetupThread function there is a call to SDL_GetHintBoolean that returns from function without naming anything if SDL_HINT_WINDOWS_... is false.

Still, finding way around this bug doesn't mean it won't come back to haunt me from some other library naming its threads.

SDL2 & GDB: program received signal ?, unknown signal

Solution

Problem