SDL_TLSID.3type - Man Page

#include <SDL3/SDL_thread.h>

typedef SDL_AtomicInt SDL_TLSID;

0 is the invalid ID. An app can create these and then set data for these IDs that is unique to each thread.

This datatype is available since SDL 3.2.0.

SDL_GetTLS(3), SDL_SetTLS(3)