Get the value of a special SDL/OpenGL attribute
Returns 0 on success, or -1 on an error.
Places the value of the SDL/OpenGL attribute attr into value. This is useful after a call to SDL_SetVideoMode to check whether your attributes have been set as you expected.
Binds to C-function call in SDL_video.h:
int SDL_GL_GetAttribute(SDLGLattr attr, int *value)