SDL simple threading produces segmentation fault - c

Question

I've been trying to use SDL threading, but I've not been able to make it work properly. Even the simplest programs cause a segmentation fault.
I'm using mingw64 (not mingw32) inside the cygwin environment.
This code produces a segmentation fault both when run inside cygwin and outside it:
#include <SDL.h>
#include <SDL_thread.h>
int threadFunction(void* data) {
return 0;
}
int main(int argc,char* argv[]) {
int dataIn=0;
int dataOut=0;
SDL_Thread* thread;
SDL_Window* window;
SDL_Init(0);
thread=SDL_CreateThread(&threadFunction,"Thread",&dataIn);
SDL_WaitThread(thread,&dataOut);
SDL_Quit();
return 0;
}
However, once printf statements are added in between, like so:
SDL_Init(0);
printf("#1 ");
thread=SDL_CreateThread(&threadFunction,"Thread",&dataIn);
printf("#2 ");
SDL_WaitThread(thread,&dataOut);
printf("#3 ");
SDL_Quit();
printf("#4 ");
return 0;
Something very strange happens. When this code is run inside the cygwin environment, either with or without the -mwindows option, it works ok. The program exits normally. When this same code is run outside the cygwin environment it crashes only without the -mwindows option. Rearranging the printf's around has diverse results, sometimes making it crash and sometimes not.
When this code is run, the output is this:
Cygwin: ./test -> #1 #2 #3 #4
Windows: test -> #1 (program freezes and a "test.exe has stopped working" window appears)
The compilation command I'm using is this: gcc -I./SDL2 -o test test.c -lmingw32 -lSDL2main -lSDL2 where gcc is a symlink to the x86_64 version of the mingw64 C compiler. I've also tried with the normal x86 (i386, 32-bits) version of mingw64/SDL and the same thing happens.
When compiling with the -g option and using gdb on the first example (without printf's) this is shown:
Starting program: /Test/test
[New Thread 5828.0x1084]
Program received signal SIGSEGV, Segmentation fault.
0x000000006c868e30 in ?? () from /Test/SDL2.dll
(gdb) where
#0 0x000000006c868e30 in ?? () from /Test/SDL2.dll
#1 0x000000006c830d29 in SDL_LogCritical ()
from /Test/SDL2.dll
#2 0x000000006c7cb85f in SDL_LogCritical ()
from /Test/SDL2.dll
#3 0x0000000000401600 in SDL_main (argc=1, argv=0x2f0010) at test.c:17
#4 0x0000000000402cfa in console_main ()
#5 0x0000000000402db1 in WinMain ()
#6 0x00000000004013e8 in __tmainCRTStartup ()
at /usr/src/debug/mingw64-x86_64-runtime-4.0.6-1/crt/crtexe.c:332
#7 0x000000000040151b in mainCRTStartup ()
at /usr/src/debug/mingw64-x86_64-runtime-4.0.6-1/crt/crtexe.c:212
Whereas the printf version:
Starting program: /home/Mimi/Escocia/C/Test/test
[New Thread 3380.0x98c]
[New Thread 3380.0x1a80]
[Thread 3380.0x1a80 exited with code 0]
#1 #2 #3 #4 [Inferior 1 (process 3380) exited normally]
(But running this program outside cygwin produces a segfault)
Is linking with libmingw32 on mingw64 wrong? (It doesn't seem right either, but it didn't compile without it.) Am I missing something obvious? Does anybody know what I'm doing wrong? Is it a bug? (If it is, where should I report it to: SDL, mingw64 or Cygwin?)
Thanks in advance.
EDIT: After recompiling SDL the problem is gone. Does anyone know why does it work now? Are there any disadvantages to compiling it myself?