strptime

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

NAME
       strptime  - convert a string representation of time to a time tm struc-
       ture

SYNOPSIS
       #define _XOPEN_SOURCE       /* See feature_test_macros(7) */
       #include <time.h>

       char *strptime(const char *s, const char *format, struct tm *tm);

DESCRIPTION
       The strptime() function is the converse of strftime(3); it converts the
       character  string  pointed  to  by  s to values which are stored in the
       "broken-down time" structure pointed to by tm, using the format  speci-
       fied by format.

       The broken-down time structure tm is defined in <time.h> as follows:

           struct tm {
               int tm_sec;    /* Seconds (0-60) */
               int tm_min;    /* Minutes (0-59) */
               int tm_hour;   /* Hours (0-23) */
               int tm_mday;   /* Day of the month (1-31) */
               int tm_mon;    /* Month (0-11) */
               int tm_year;   /* Year - 1900 */
               int tm_wday;   /* Day of the week (0-6, Sunday = 0) */
               int tm_yday;   /* Day in the year (0-365, 1 Jan = 0) */
               int tm_isdst;  /* Daylight saving time */
           };

       For more details on the tm structure, see ctime(3).

       The  format  argument  is a character string that consists of field de-
       scriptors and text characters, reminiscent of scanf(3).  Each field de-
       scriptor  consists  of a % character followed by another character that
       specifies the replacement for the field descriptor.  All other  charac-
       ters  in  the format string must have a matching character in the input
       string, except for whitespace, which matches zero  or  more  whitespace
       characters  in  the  input string.  There should be whitespace or other
       alphanumeric characters between any two field descriptors.

       The strptime() function processes the input string from left to  right.
       Each of the three possible input elements (whitespace, literal, or for-
       mat) are handled one after the other.  If the input cannot  be  matched
       to  the format string, the function stops.  The remainder of the format
       and input strings are not processed.

       The supported input field descriptors are listed below.  In case a text
       string (such as the name of a day of the week or a month name) is to be
       matched, the comparison is case insensitive.  In case a number is to be
       matched, leading zeros are permitted but not required.

       %%     The % character.

       %a or %A
              The name of the day of the week according to the current locale,
              in abbreviated form or the full name.

       %b or %B or %h
              The month name according to the current locale,  in  abbreviated
              form or the full name.

       %c     The date and time representation for the current locale.

       %C     The century number (0-99).

       %d or %e
              The day of month (1-31).

       %D     Equivalent  to %m/%d/%y.  (This is the American style date, very
              confusing to non-Americans, especially since %d/%m/%y is  widely
              used in Europe.  The ISO 8601 standard format is %Y-%m-%d.)

       %H     The hour (0-23).

       %I     The hour on a 12-hour clock (1-12).

       %j     The day number in the year (1-366).

       %m     The month number (1-12).

       %M     The minute (0-59).

       %n     Arbitrary whitespace.

       %p     The locale's equivalent of AM or PM.  (Note: there may be none.)

       %r     The  12-hour  clock  time (using the locale's AM or PM).  In the
              POSIX locale equivalent to %I:%M:%S %p.  If t_fmt_ampm is  empty
              in  the LC_TIME part of the current locale, then the behavior is
              undefined.

       %R     Equivalent to %H:%M.

       %S     The second (0-60; 60 may occur for leap seconds; earlier also 61
              was allowed).

       %t     Arbitrary whitespace.

       %T     Equivalent to %H:%M:%S.

       %U     The  week  number  with Sunday the first day of the week (0-53).
              The first Sunday of January is the first day of week 1.

       %w     The ordinal number of the day of the week (0-6), with  Sunday  =
              0.

       %W     The  week  number  with Monday the first day of the week (0-53).
              The first Monday of January is the first day of week 1.

       %x     The date, using the locale's date format.

       %X     The time, using the locale's time format.

       %y     The year within century (0-99).  When a century is not otherwise
              specified, values in the range 69-99 refer to years in the twen-
              tieth century (1969-1999); values in the range  00-68  refer  to
              years in the twenty-first century (2000-2068).

       %Y     The year, including century (for example, 1991).

       Some  field  descriptors can be modified by the E or O modifier charac-
       ters to indicate that an alternative format or specification should  be
       used.  If the alternative format or specification does not exist in the
       current locale, the unmodified field descriptor is used.

       The E modifier specifies that the input string may contain  alternative
       locale-dependent versions of the date and time representation:

       %Ec    The locale's alternative date and time representation.

       %EC    The  name  of the base year (period) in the locale's alternative
              representation.

       %Ex    The locale's alternative date representation.

       %EX    The locale's alternative time representation.

       %Ey    The offset from %EC (year only) in the locale's alternative rep-
              resentation.

       %EY    The full alternative year representation.

       The O modifier specifies that the numerical input may be in an alterna-
       tive locale-dependent format:

       %Od or %Oe
              The day of the month using the locale's alternative numeric sym-
              bols; leading zeros are permitted but not required.

       %OH    The  hour (24-hour clock) using the locale's alternative numeric
              symbols.

       %OI    The hour (12-hour clock) using the locale's alternative  numeric
              symbols.

       %Om    The month using the locale's alternative numeric symbols.

       %OM    The minutes using the locale's alternative numeric symbols.

       %OS    The seconds using the locale's alternative numeric symbols.

       %OU    The  week  number  of  the  year (Sunday as the first day of the
              week) using the locale's alternative numeric symbols.

       %Ow    The ordinal number of the day of the week (Sunday=0),
               using the locale's alternative numeric symbols.

       %OW    The week number of the year (Monday as  the  first  day  of  the
              week) using the locale's alternative numeric symbols.

       %Oy    The year (offset from %C) using the locale's alternative numeric
              symbols.

RETURN VALUE
       The return value of the function is a pointer to  the  first  character
       not processed in this function call.  In case the input string contains
       more characters than required by the format string,  the  return  value
       points  right  after  the  last  consumed input character.  In case the
       whole input string is consumed, the return value  points  to  the  null
       byte at the end of the string.  If strptime() fails to match all of the
       format string and therefore an error  occurred,  the  function  returns
       NULL.

ATTRIBUTES
       For  an  explanation  of  the  terms  used  in  this  section,  see at-
       tributes(7).

       +-----------+---------------+--------------------+
       |Interface  | Attribute     | Value              |
       +-----------+---------------+--------------------+
       |strptime() | Thread safety | MT-Safe env locale |
       +-----------+---------------+--------------------+
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008, SUSv2.

NOTES
       In principle, this function does not initialize tm but stores only  the
       values  specified.  This means that tm should be initialized before the
       call.  Details differ a bit between different UNIX systems.  The  glibc
       implementation  does  not  touch  those fields which are not explicitly
       specified, except that it recomputes the tm_wday and tm_yday  field  if
       any of the year, month, or day elements changed.

       The  'y'  (year in century) specification is taken to specify a year in
       the range 1950-2049 by glibc  2.0.   It  is  taken  to  be  a  year  in
       1969-2068 since glibc 2.1.

   Glibc notes
       For reasons of symmetry, glibc tries to support for strptime() the same
       format characters as for strftime(3).  (In most cases, the  correspond-
       ing fields are parsed, but no field in tm is changed.)  This leads to

       %F     Equivalent to %Y-%m-%d, the ISO 8601 date format.

       %g     The  year  corresponding to the ISO week number, but without the
              century (0-99).

       %G     The year corresponding to the ISO week  number.   (For  example,
              1991.)

       %u     The day of the week as a decimal number (1-7, where Monday = 1).

       %V     The  ISO  8601:1988  week number as a decimal number (1-53).  If
              the week (starting on Monday) containing 1 January has  four  or
              more days in the new year, then it is considered week 1.  Other-
              wise, it is the last week of the previous  year,  and  the  next
              week is week 1.

       %z     An RFC-822/ISO 8601 standard timezone specification.

       %Z     The timezone name.

       Similarly,  because of GNU extensions to strftime(3), %k is accepted as
       a synonym for %H, and %l should be accepted as a synonym for %I, and %P
       is accepted as a synonym for %p.  Finally

       %s     The number of seconds since the Epoch, 1970-01-01 00:00:00 +0000
              (UTC).  Leap seconds are not counted unless leap second  support
              is available.

       The  glibc implementation does not require whitespace between two field
       descriptors.

EXAMPLE
       The following example demonstrates the  use  of  strptime()  and  strf-
       time(3).

       #define _XOPEN_SOURCE
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>
       #include <time.h>

       int
       main(void)
       {
           struct tm tm;
           char buf[255];

           memset(&tm, 0, sizeof(struct tm));
           strptime("2001-11-12 18:31:01", "%Y-%m-%d %H:%M:%S", &tm);
           strftime(buf, sizeof(buf), "%d %b %Y %H:%M", &tm);
           puts(buf);
           exit(EXIT_SUCCESS);
       }

SEE ALSO
       time(2), getdate(3), scanf(3), setlocale(3), strftime(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/.

GNU                               2017-09-15                       STRPTIME(3)
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