DOKK / manpages / debian 13 / libsdl3-doc / SDL_PEN_TOUCHID.3.en
SDL_PEN_TOUCHID(3) SDL3 FUNCTIONS SDL_PEN_TOUCHID(3)

SDL_PEN_TOUCHID - The SDL_TouchID
for touch events simulated with pen input.

Defined in SDL3/SDL_pen.h

#include "SDL3/SDL.h"
#define SDL_PEN_TOUCHID ((SDL_TouchID)-2)

This macro is available since SDL 3.2.0.

SDL 3.2.10 Simple Directmedia Layer