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man: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
     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  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
     attributes(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

     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
     https://www.kernel.org/doc/man-pages/.

GNU 2017-09-15 STRPTIME(3)

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