strftime -- format date and time
Standard C Library (libc, -lc)
#include <time.h>
size_t
strftime(char * restrict buf, size_t maxsize,
const char * restrict format, const struct tm * restrict timeptr);
DESCRIPTION [Toc]
The strftime() function formats the information from timeptr into the
buffer buf according to the string pointed to by format.
The format string consists of zero or more conversion specifications and
ordinary characters. All ordinary characters are copied directly into
the buffer. A conversion specification consists of a percent sign
```%''' and one other character.
No more than maxsize characters will be placed into the array. If the
total number of resulting characters, including the terminating NUL character,
is not more than maxsize, strftime() returns the number of characters
in the array, not counting the terminating NUL. Otherwise, zero is
returned and the buffer contents are indeterminate.
The conversion specifications are copied to the buffer after expansion as
follows:-
%A is replaced by national representation of the full weekday name.
%a is replaced by national representation of the abbreviated weekday
name.
%B is replaced by national representation of the full month name.
%b is replaced by national representation of the abbreviated month
name.
%C is replaced by (year / 100) as decimal number; single digits are
preceded by a zero.
%c is replaced by national representation of time and date.
%D is equivalent to ``%m/%d/%y''.
%d is replaced by the day of the month as a decimal number (01-31).
%E* %O*
POSIX locale extensions. The sequences %Ec %EC %Ex %EX %Ey %EY %Od
%Oe %OH %OI %Om %OM %OS %Ou %OU %OV %Ow %OW %Oy are supposed to
provide alternate representations.
Additionly %OB implemented to represent alternative months names
(used standalone, without day mentioned).
%e is replaced by the day of month as a decimal number (1-31); single
digits are preceded by a blank.
%F is equivalent to ``%Y-%m-%d''.
%G is replaced by a year as a decimal number with century. This year
is the one that contains the greater part of the week (Monday as
the first day of the week).
%g is replaced by the same year as in ``%G'', but as a decimal number
without century (00-99).
%H is replaced by the hour (24-hour clock) as a decimal number
(00-23).
%h the same as %b.
%I is replaced by the hour (12-hour clock) as a decimal number
(01-12).
%j is replaced by the day of the year as a decimal number (001-366).
%k is replaced by the hour (24-hour clock) as a decimal number (0-23);
single digits are preceded by a blank.
%l is replaced by the hour (12-hour clock) as a decimal number (1-12);
single digits are preceded by a blank.
%M is replaced by the minute as a decimal number (00-59).
%m is replaced by the month as a decimal number (01-12).
%n is replaced by a newline.
%O* the same as %E*.
%p is replaced by national representation of either "ante meridiem" or
"post meridiem" as appropriate.
%R is equivalent to ``%H:%M''.
%r is equivalent to ``%I:%M:%S %p''.
%S is replaced by the second as a decimal number (00-60).
%s is replaced by the number of seconds since the Epoch, UTC (see
mktime(3)).
%T is equivalent to ``%H:%M:%S''.
%t is replaced by a tab.
%U is replaced by the week number of the year (Sunday as the first day
of the week) as a decimal number (00-53).
%u is replaced by the weekday (Monday as the first day of the week) as
a decimal number (1-7).
%V is replaced by the week number of the year (Monday as the first day
of the week) as a decimal number (01-53). If the week containing
January 1 has four or more days in the new year, then it is week 1;
otherwise it is the last week of the previous year, and the next
week is week 1.
%v is equivalent to ``%e-%b-%Y''.
%W is replaced by the week number of the year (Monday as the first day
of the week) as a decimal number (00-53).
%w is replaced by the weekday (Sunday as the first day of the week) as
a decimal number (0-6).
%X is replaced by national representation of the time.
%x is replaced by national representation of the date.
%Y is replaced by the year with century as a decimal number.
%y is replaced by the year without century as a decimal number
(00-99).
%Z is replaced by the time zone name.
%z is replaced by the time zone offset from UTC; a leading plus sign
stands for east of UTC, a minus sign for west of UTC, hours and
minutes follow with two digits each and no delimiter between them
(common form for RFC 822 date headers).
%+ is replaced by national representation of the date and time (the
format is similar to that produced by date(1)).
%% is replaced by `%'.
date(1), printf(1), ctime(3), printf(3), strptime(3), wcsftime(3)
The strftime() function conforms to ISO/IEC 9899:1990 (``ISO C89'') with
a lot of extensions including `%C', `%D', `%E*', `%e', `%G', `%g', `%h',
`%k', `%l', `%n', `%O*', `%R', `%r', `%s', `%T', `%t', `%u', `%V', `%z',
`%+'.
The peculiar week number and year in the replacements of `%G', `%g' and
`%V' are defined in ISO 8601: 1988.
There is no conversion specification for the phase of the moon.
The strftime() function does not correctly handle multibyte characters in
the format argument.
FreeBSD 5.2.1 January 4, 2003 FreeBSD 5.2.1