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

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

       #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)):

           _XOPEN_SOURCE >= 500

       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,  ei-
       ther 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-

       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.   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.

       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-

       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.

              File containing format patterns.

       TZ, LC_TIME
              Variables used by strptime(3).

       For an  explanation  of  the  terms  used  in  this  section,  see  at-

       |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 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.

       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 re-
       turned tm structure.  The following shell session demonstrates the  op-
       eration 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>

       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);

               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);


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

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                                  2019-03-06                        GETDATE(3)
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