xenial (3) strptime.3.gz

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NAME

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

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
       specified 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 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).

       ┌───────────┬───────────────┬────────────────────┐
       │InterfaceAttributeValue              │
       ├───────────┼───────────────┼────────────────────┤
       │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 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.

EXAMPLE

       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(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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