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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,
     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-
     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
     allbox;  lb  lb  lb  l  l  l.   Interface Attribute Value  T{ getdate()
     T}   Thread safety     MT-Unsafe race:getdate env locale T{ getdate_r()
     T}   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
     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
     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);
             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 4.16 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
                                2017-09-15                        GETDATE(3)
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