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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 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
       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
       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 weekday 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.
       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.

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
           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

       DATEMSK
              File containing format patterns.

       TZ, LC_TIME
              Variables used by strptime(3).

CONFORMING TO

       POSIX.1-2001.

NOTES

       The  POSIX.1-2001  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.

EXAMPLE

       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 weekday name
           $ 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 500
       #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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                                  2010-09-20                        GETDATE(3)