|
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ENVIRONMENT | ATTRIBUTES | CONFORMING TO | NOTES | EXAMPLE | SEE ALSO | COLOPHON |
GETDATE(3) Linux Programmer's Manual GETDATE(3)
getdate, getdate_r - convert a date-plus-time string to broken-down
time
#include <time.h>
struct tm *getdate(const char *string);
extern int getdate_err;
#include <time.h>
int getdate_r(const char *string, struct tm *res);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
getdate():
_XOPEN_SOURCE >= 500
getdate_r():
_GNU_SOURCE
The function getdate() converts a string representation of a date and
time, contained in the buffer pointed to by string, into a broken-
down time. The broken-down time is stored in a tm structure, and a
pointer to this structure is returned as the function result. This
tm structure is allocated in static storage, and consequently it will
be overwritten by further calls to getdate().
In contrast to strptime(3), (which has a format argument), getdate()
uses the formats found in the file whose full pathname 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
specified in POSIX.1-2001:
%Z Timezone name. This is not implemented in glibc.
When %Z is given, the structure containing the broken-down time is
initialized with values corresponding to the current time in the
given timezone. Otherwise, the structure is initialized to the
broken-down time corresponding to the current local time (as by a
call to localtime(3)).
When only the day of the week is given, the day is taken to be the
first such day on or after today.
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 month.
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.
getdate_r() is a GNU extension that provides a reentrant version of
getdate(). Rather than using a global variable to report errors and
a static buffer to return the broken down time, it returns errors via
the function result value, and returns the resulting broken-down time
in the caller-allocated buffer pointed to by the argument res.
When successful, getdate() returns a pointer to a struct tm.
Otherwise, it returns NULL and sets the global variable getdate_err
to one of the error numbers shown below. Changes to errno are
unspecified.
On success getdate_r() returns 0; on error it returns one of the
error numbers shown below.
The following errors are returned via getdate_err (for getdate()) or
as the function result (for getdate_r()):
1 The DATEMSK environment variable is not defined, or its value is
an empty string.
2 The template file specified by DATEMSK cannot be opened for
reading.
3 Failed to get file status information.
4 The template file is not a regular file.
5 An error was 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.
DATEMSK
File containing format patterns.
TZ, LC_TIME
Variables used by strptime(3).
For an explanation of the terms used in this section, see
attributes(7).
┌────────────┬───────────────┬───────────────────────────────────┐
│Interface │ Attribute │ Value │
├────────────┼───────────────┼───────────────────────────────────┤
│getdate() │ Thread safety │ MT-Unsafe race:getdate env locale │
├────────────┼───────────────┼───────────────────────────────────┤
│getdate_r() │ Thread safety │ MT-Safe env locale │
└────────────┴───────────────┴───────────────────────────────────┘
POSIX.1-2001, POSIX.1-2008.
The POSIX.1 specification for strptime(3) contains conversion
specifications using the %E or %O modifier, while such specifications
are not given for getdate(). In glibc, getdate() is implemented
using strptime(3), so that precisely the same conversions are
supported by both.
The program below calls getdate() for each of its command-line
arguments, and for each call displays the values in the fields of the
returned tm structure. The following shell session demonstrates the
operation of the program:
$ TFILE=$PWD/tfile
$ echo '%A' > $TFILE # Full name of the day of the week
$ echo '%T' >> $TFILE # ISO date (YYYY-MM-DD)
$ echo '%F' >> $TFILE # Time (HH:MM:SS)
$ date
$ export DATEMSK=$TFILE
$ ./a.out Tuesday '2009-12-28' '12:22:33'
Sun Sep 7 06:03:36 CEST 2008
Call 1 ("Tuesday") succeeded:
tm_sec = 36
tm_min = 3
tm_hour = 6
tm_mday = 9
tm_mon = 8
tm_year = 108
tm_wday = 2
tm_yday = 252
tm_isdst = 1
Call 2 ("2009-12-28") succeeded:
tm_sec = 36
tm_min = 3
tm_hour = 6
tm_mday = 28
tm_mon = 11
tm_year = 109
tm_wday = 1
tm_yday = 361
tm_isdst = 0
Call 3 ("12:22:33") succeeded:
tm_sec = 33
tm_min = 22
tm_hour = 12
tm_mday = 7
tm_mon = 8
tm_year = 108
tm_wday = 0
tm_yday = 250
tm_isdst = 1
Program source
#define _GNU_SOURCE
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
int
main(int argc, char *argv[])
{
struct tm *tmp;
int j;
for (j = 1; j < argc; j++) {
tmp = getdate(argv[j]);
if (tmp == NULL) {
printf("Call %d failed; getdate_err = %d\n",
j, getdate_err);
continue;
}
printf("Call %d (\"%s\") succeeded:\n", j, argv[j]);
printf(" tm_sec = %d\n", tmp->tm_sec);
printf(" tm_min = %d\n", tmp->tm_min);
printf(" tm_hour = %d\n", tmp->tm_hour);
printf(" tm_mday = %d\n", tmp->tm_mday);
printf(" tm_mon = %d\n", tmp->tm_mon);
printf(" tm_year = %d\n", tmp->tm_year);
printf(" tm_wday = %d\n", tmp->tm_wday);
printf(" tm_yday = %d\n", tmp->tm_yday);
printf(" tm_isdst = %d\n", tmp->tm_isdst);
}
exit(EXIT_SUCCESS);
}
time(2), localtime(3), setlocale(3), strftime(3), strptime(3)
This page is part of release 4.12 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
2016-03-15 GETDATE(3)
Pages that refer to this page: strptime(3)