SDL_GetVideoInfo (3) - Linux Manuals
SDL_GetVideoInfo: returns a pointer to information about the video hardware
NAME
SDL_GetVideoInfo - returns a pointer to information about the video hardwareSYNOPSIS
#include "SDL.h"
SDL_VideoInfo *SDL_GetVideoInfo(void);
DESCRIPTION
This function returns a read-only pointer to information about the video hardware. If this is called before SDL_SetVideoMode, the vfmt member of the returned structure will contain the pixel format of the "best" video mode.
SEE ALSO
SDL_SetVideoMode, SDL_VideoInfo