GETDATE(3) Linux Programmer's Manual GETDATE(3)
getdate() - convert a string to struct tm
struct tm *getdate (const char *string);
extern int getdate_err;
int getdate_r (const char *string, struct tm *res);
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 over-
written 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
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:
%Z Timezone name.
When %Z is given, the value to be returned is initialised to the broken-down time corre-
sponding to the current time in the given time zone. Otherwise, it is initialised to the
broken-down time corresponding to the current local time.
When only the weekday is given, the day is taken to be the first such day on or after
When only the month is given (and no year), the month is taken to be the first such month
equal to or after the current month. If no day is given, it is the first day of the
When no hour, minute and second are given, the current hour, minute and second are taken.
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.
When successful, this function returns a pointer to a struct tm. Otherwise, it returns
NULL and sets the global variable getdate_err. Changes to errno are unspecified. The
following values for getdate_err are defined:
1 The DATEMSK environment variable is null or undefined.
2 The template file cannot be opened for reading.
3 Failed to get file status information.
4 The template file is not a regular file.
5 An error is encountered while reading the template file.
6 Memory allocation failed (not enough memory available).
7 There is no line in the file that matches the input.
8 Invalid input specification.
Since getdate() is not reentrant because of the use of getdate_err and the static buffer
to return the result in, glibc provides a thread-safe variant. The functionality is the
same. The result is returned in the buffer pointed to by res and in case of an error the
return value is nonzero with the same values as given above for getdate_err.
The POSIX 1003.1-2001 specification for strptime() contains conversion specifications
using the %E or %O modifier, while such specifications are not given for getdate(). The
glibc implementation implements getdate() using strptime() so that automatically precisely
the same conversions are supported by both.
The glibc implementation does not support the %Z conversion specification.
File containing format patterns.
Variables used by strptime().
ISO 9899, POSIX 1003.1-2001
localtime(3), strftime(3), strptime(3), time(3)