Note that SDL_GUIDToString() and SDL_StringToGUID() are thread-safe.

include/SDL3/SDL_guid.h

@@ -71,6 +71,8 @@ typedef struct SDL_GUID {
  * \param pszGUID buffer in which to write the ASCII string.
  * \param cbGUID the size of pszGUID, should be at least 33 bytes.
  *
+ * \threadsafety It is safe to call this function from any thread.
+ *
  * \since This function is available since SDL 3.2.0.
  *
  * \sa SDL_StringToGUID
@@ -87,6 +89,8 @@ extern SDL_DECLSPEC void SDLCALL SDL_GUIDToString(SDL_GUID guid, char *pszGUID,
  * \param pchGUID string containing an ASCII representation of a GUID.
  * \returns a SDL_GUID structure.
  *
+ * \threadsafety It is safe to call this function from any thread.
+ *
  * \since This function is available since SDL 3.2.0.
  *
  * \sa SDL_GUIDToString