getdate(3) - Linux manual page (original) (raw)
getdate(3) Library Functions Manual getdate(3)
NAME top
getdate, getdate_r - convert a date-plus-time string to broken-
down timeLIBRARY top
Standard C library (_libc_, _-lc_)SYNOPSIS top
**#include <time.h>**
**struct tm *getdate(const char ***_string_**);**
**extern int getdate_err;**
**int getdate_r(const char *restrict** _string_**, struct tm *restrict** _res_**);**Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
**getdate**():
_XOPEN_SOURCE >= 500
**getdate_r**():
_GNU_SOURCEDESCRIPTION top
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)](../man3/strptime.3.html), (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)](../man3/strptime.3.html). 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)](../man3/localtime.3.html)).
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_.RETURN VALUE top
When successful, **getdate**() returns a pointer to a _struct tm_.
Otherwise, it returns NULL and sets the global variable
_getdateerr_ to one of the error numbers shown below. Changes to
_[errno](../man3/errno.3.html)_ are unspecified.
On success **getdate_r**() returns 0; on error it returns one of the
error numbers shown below.ERRORS top
The following errors are returned via _getdateerr_ (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.ENVIRONMENT top
**DATEMSK**
File containing format patterns.
**TZ**
**LC_TIME**
Variables used by [strptime(3)](../man3/strptime.3.html).ATTRIBUTES top
For an explanation of the terms used in this section, see
[attributes(7)](../man7/attributes.7.html).
┌─────────────┬───────────────┬──────────────────────────────────┐
│ **Interface** │ **Attribute** │ **Value** │
├─────────────┼───────────────┼──────────────────────────────────┤
│ **getdate**() │ Thread safety │ MT-Unsafe race:getdate env │
│ │ │ locale │
├─────────────┼───────────────┼──────────────────────────────────┤
│ **getdate_r**() │ Thread safety │ MT-Safe env locale │
└─────────────┴───────────────┴──────────────────────────────────┘VERSIONS top
The POSIX.1 specification for [strptime(3)](../man3/strptime.3.html) 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)](../man3/strptime.3.html), so that precisely the same
conversions are supported by both.STANDARDS top
POSIX.1-2008.HISTORY top
POSIX.1-2001.EXAMPLES top
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** # Time (HH:MM:SS)
$ **echo '%F' >> $TFILE** # ISO date (YYYY-MM-DD)
$ **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 = 1Program source
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int
main(int argc, char *argv[])
{
struct tm *tmp;
for (size_t j = 1; j < argc; j++) {
tmp = getdate(argv[j]);
if (tmp == NULL) {
printf("Call %zu failed; getdate_err = %d\n",
j, getdate_err);
continue;
}
printf("Call %zu (\"%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);
}SEE ALSO top
[time(2)](../man2/time.2.html), [localtime(3)](../man3/localtime.3.html), [setlocale(3)](../man3/setlocale.3.html), [strftime(3)](../man3/strftime.3.html), [strptime(3)](../man3/strptime.3.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 getdate(3)
Pages that refer to this page:strptime(3)