# strptime

## NAME



           strptime - convert a string representation of time to a time tm
           structure
    


## LIBRARY



           Standard C library (_libc_ , _-lc_)
    


## SYNOPSIS



           **#define _XOPEN_SOURCE** /* See feature_test_macros(7) */
           **#include <time.h>**
    
           **char *strptime(const char *restrict** _s_**, const char *restrict** _format_**,**
                          **struct tm *restrict** _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 specified by _format_.
    
           The broken-down time structure _tm_ is described in tm(3type).
    
           The _format_ argument is a character string that consists of field
           descriptors and text characters, reminiscent of scanf(3).  Each
           field descriptor consists of a **%** character followed by another
           character that specifies the replacement for the field descriptor.
           All other characters 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 format) 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 twentieth 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
           characters 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
                  representation.
    
           **%EY** The full alternative year representation.
    
           The O modifier specifies that the numerical input may be in an
           alternative locale-dependent format:
    
           **%Od** or **%Oe**
                  The day of the month using the locale's alternative numeric
                  symbols; 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
           attributes(7).
           ┌───────────────────────────┬───────────────┬────────────────────┐
           │ **Interface** │ **Attribute** │ **Value** │
           ├───────────────────────────┼───────────────┼────────────────────┤
           │ **strptime**()                │ Thread safety │ MT-Safe env locale │
           └───────────────────────────┴───────────────┴────────────────────┘
    


## STANDARDS



           POSIX.1-2008.
    


## 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
           corresponding 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.  Otherwise, 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.
    


## EXAMPLES



           The following example demonstrates the use of **strptime**() and
           strftime(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(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);
           }
    


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