On Thu, 2023-06-29 at 10:23 +0100, Jonathan Wakely wrote: > That macro isn't even defined until later in the file, so would never > be defined at this point. Was a simplified example. Why do you still need to have some mutexes or whatever in case TZDB_DISABLED? > It should always be possible to call std::chrono::get_tzdb() even if the tzdb only contains the UTC time zone. Just return NULL in case TZDB_DISABLED? Thanks