The old code used a blanket 64 byte buffer and strncpy()'d a locale name into it for separator normalization ('-' → '_') followed by lookup into windows_to_iso_list. But the latter has space for only five character (excluding the terminating null), so any matching string must needs be less than six characters in size, so check and reject such inputs very early in the function. Then, reduce the buffer size to what windows_to_iso_list uses, too. This means the strncpy() is guaranteed to write the terminating null, so we can skip doing it manually, and it won't waste time filling the remaining 58 octets of the buffer with null bytes anymore (which it did!). Now that both buffer sizes match, we could almost use memcmp(), but the table isn't ready, yet, so that's left for a different patch. Add some code comments. Amends c17563eca879845deef542173f5fb479c9aa2d0e (though that might have just moved existing code around; didn't check). Pick-to: 6.10 6.9 6.8 6.5 Change-Id: I715d5435aed874ce7141ff25c2753e0886184516 Reviewed-by: Ivan Solovev <ivan.solovev@qt.io> Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>