SDL_WINDOWPOS_UNDEFINED - Man Page

Used to indicate that you don't care what the window position/display is.

Header File

Defined in SDL3/SDL_video.h

#include "SDL3/SDL.h"

#define SDL_WINDOWPOS_UNDEFINED         SDL_WINDOWPOS_UNDEFINED_DISPLAY(0)

This always uses the primary display.

This macro is available since SDL 3.2.0.

SDL 3.2.2 Simple Directmedia Layer SDL3 FUNCTIONS