`strftime` incorrect return value

[sprintersb]

From man strftime:

RETURN VALUE

Provided that the result string, including the terminating null byte, does not exceed max bytes, strftime() returns the number of bytes (excluding the terminating null byte) placed in the array s. If the length of the result string (including the terminating null byte) would exceed max bytes, then strftime() returns 0, and the contents of the array are undefined.

This is not how strftime() behaves.