GETDATE(3)		   Linux Programmer's Manual		    GETDATE(3)



NAME
       getdate,	 getdate_r  -  convert	a date-plus-time string to broken-down
       time

SYNOPSIS
       #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

DESCRIPTION
       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 struc-
       ture is allocated in static storage, and consequently it will be	 over-
       written 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 ini-
       tialized 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	local-
       time(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.

RETURN VALUE
       When successful, getdate() returns a pointer to a  struct  tm.	Other-
       wise,  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.

ERRORS
       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 read-
	   ing.

       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
       DATEMSK
	      File containing format patterns.

       TZ, LC_TIME
	      Variables used by strptime(3).

ATTRIBUTES
       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		|
       +------------+---------------+-----------------------------------+
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

NOTES
       The  POSIX.1 specification for strptime(3) contains conversion specifi-
       cations using the %E or %O modifier, while such specifications are  not
       given  for  getdate().	In glibc, getdate() is implemented using strp-
       time(3), so that precisely the same conversions are supported by both.

EXAMPLE
       The program below calls getdate() for each of  its  command-line	 argu-
       ments,  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);
       }

SEE ALSO
       time(2), localtime(3), setlocale(3), strftime(3), strptime(3)

COLOPHON
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       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)