SDL_PenID.3type - Man Page

#include <SDL3/SDL_pen.h>

typedef Uint32 SDL_PenID;

Zero is used to signify an invalid/null device.

These show up in pen events when SDL sees input from them. They remain consistent as long as SDL can recognize a tool to be the same pen; but if a pen's digitizer table is physically detached from the computer, it might get a new ID when reconnected, as SDL won't know it's the same device.

These IDs are only stable within a single run of a program; the next time a program is run, the pen's ID will likely be different, even if the hardware hasn't been disconnected, etc.

This datatype is available since SDL 3.2.0.