SDL_GetDisplayBounds

Get the desktop area represented by a display.

Syntax

int SDL_GetDisplayBounds(int displayIndex, SDL_Rect * rect);

displayIndex	the index of the display to query
rect	the SDL_Rect structure filled in with the display bounds

Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.

The primary display (displayIndex zero) is always located at 0,0.

SDL_Rect r;
if (SDL_GetDisplayBounds(0, &r) != 0) {
    SDL_Log("SDL_GetDisplayBounds failed: %s", SDL_GetError());
    return 1;
}