The function getdate() converts a string pointed to by string into the tm structure that it returns. This tm structure may be found in static storage, so that it will be overwritten by the next call.
In contrast to strptime(3), (which has a format argument), getdate() uses the formats found in the file of which the full path name is given in the environment variable DATEMSK. The first line in the file that matches the given input string is used for the conversion.
The matching is done case insensitively. Superfluous whitespace, either in the pattern or in the string to be converted, is ignored.
The conversion specifications that a pattern can contain are those given for strptime(3). One more conversion specification is accepted: