The match between the template and input specification performed by getdate() shall be case-insensitive.The month and weekday names can consist of any combination of upper and lowercase letters.The external variable or macro getdate_err is used by getdate() to return error values.
When successful, getdate() returns a pointer to a struct tm.
If no date is given, but we know the hour, then that hour is taken to be the first such hour equal to or after the current hour.
getdate_r() is a GNU extension that provides a reentrant version of getdate().
The templates are contained in a text file identified by the environment variable DATEMSK .
The DATEMSK variable should be set to indicate the full pathname of the file that contains the templates.