View Source: strftime(3) - Waikato Linux Users Group

Edit PageHistory Diff Info LikePages
STRFTIME
!!!STRFTIME
NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ENVIRONMENT
CONFORMING TO
SEE ALSO
----
!!NAME


strftime - format date and time
!!SYNOPSIS


__#include
__''s''__, size_t__ ''max''__, const char *__''format''__,
const struct tm *__''tm''__);
__
!!DESCRIPTION


The __strftime()__ function formats the broken-down time
''tm'' according to the format specification
''format'' and places the result in the character array
''s'' of size ''max''.


Ordinary characters placed in the format string are copied
to ''s'' without conversion. Conversion specifiers are
introduced by a `%' character, and are replaced in ''s''
as follows:


__%a__


The abbreviated weekday name according to the current
locale.


__%A__


The full weekday name according to the current
locale.


__%b__


The abbreviated month name according to the current
locale.


__%B__


The full month name according to the current
locale.


__%c__


The preferred date and time representation for the current
locale.


__%C__


The century number (year/100) as a 2-digit integer.
(SU)


__%C__


The century number (the year divided by 100 and truncated to
an integer).


__%d__


The day of the month as a decimal number (range 01 to
31).


__%D__


Equivalent to %m/%d/%y. (Yecch - for Americans only.
Americans should note that in other countries %d/%m/%y is
rather common. This means that in international context this
format is ambiguous and should not be used.)
(SU)


__%e__


Like %d, the day of the month as a decimal number, but a
leading zero is replaced by a space. (SU)


__%E__


Modifier: use alternative format, see below.
(SU)


__%G__


The ISO 8601 year with century as a decimal number. The
4-digit year corresponding to the ISO week number (see %V).
This has the same format and value as %y, except that if the
ISO week number belongs to the previous or next year, that
year is used instead. (TZ)


__%g__


Like %G, but without century, i.e., with a 2-digit year
(00-99). (TZ)


__%h__


Equivalent to %b. (SU)


__%H__


The hour as a decimal number using a 24-hour clock (range 00
to 23).


__%I__


The hour as a decimal number using a 12-hour clock (range 01
to 12).


__%j__


The day of the year as a decimal number (range 001 to
366).


__%k__


The hour (24-hour clock) as a decimal number (range 0 to
23); single digits are preceded by a blank. (See also %H.)
(TZ)


__%l__


The hour (12-hour clock) as a decimal number (range 1 to
12); single digits are preceded by a blank. (See also %I.)
(TZ)


__%m__


The month as a decimal number (range 01 to 12).


__%M__


The minute as a decimal number (range 00 to
59).


__%n__


A newline character. (SU)


__%O__


Modifier: use alternative format, see below.
(SU)


__%p__


Either `AM' or `PM' according to the given time value, or
the corresponding strings for the current locale. Noon is
treated as `pm' and midnight as `am'.


__%P__


Like %p but in lowercase: `am' or `pm' or a corresponding
string for the current locale. (GNU)


__%r__


The time in a.m. or p.m. notation. In the POSIX locale this
is equivalent to `%I:%M:%S %p'. (SU)


__%R__


The time in 24-hour notation (%H:%M). (SU) For a version
including the seconds, see %T below.


__%s__


The number of seconds since the Epoch, i.e., since
1970-01-01 00:00:00 UTC. (TZ)


__%S__


The second as a decimal number (range 00 to
61).


__%t__


A tab character. (SU)


__%T__


The time in 24-hour notation (%H:%M:%S). (SU)


__%u__


The day of the week as a decimal, range 1 to 7, Monday being
1. See also %w. (SU)


__%U__


The week number of the current year as a decimal number,
range 00 to 53, starting with the first Sunday as the first
day of week 01. See also %V and %W.


__%V__


The ISO 8601:1988 week number of the current year as a
decimal number, range 01 to 53, where week 1 is the first
week that has at least 4 days in the current year, and with
Monday as the first day of the week. See also %U and %W.
(SU)


__%w__


The day of the week as a decimal, range 0 to 6, Sunday being
0. See also %u.


__%W__


The week number of the current year as a decimal number,
range 00 to 53, starting with the first Monday as the first
day of week 01.


__%x__


The preferred date representation for the current locale
without the time.


__%X__


The preferred time representation for the current locale
without the date.


__%y__


The year as a decimal number without a century (range 00 to
99).


__%Y__


The year as a decimal number including the
century.


__%z__


The time-zone as hour offset from GMT. Required to emit
RFC822-conformant dates (using


__%Z__


The time zone or name or abbreviation.


__%+__


The date and time in date(1) format. (TZ)


__%%__


A literal `%' character.


Some conversion specifiers can be modified by preceding them
by the E or O modifier to indicate that an alternative
format should be used. If the alternative format or
specification does not exist for the current locale, the
behaviour will be as if the unmodified conversion
specification were used. (SU) The Single Unix Specification
mentions %Ec, %EC, %Ex, %EX, %Ry, %EY, %Od, %Oe, %OH, %OI,
%Om, %OM, %OS, %Ou, %OU, %OV, %Ow, %OW, %Oy, where the
effect of the O modifier is to use alternative numeric
symbols (say, roman numerals), and that of the E modifier is
to use a locale-dependent alternative
representation.


The broken-down time structure ''tm'' is defined in
''''. See also
ctime(3).
!!RETURN VALUE


The __strftime()__ function returns the number of
characters placed in the array ''s'', not including the
terminating NUL character, provided the string, including
the terminating NUL, fits. Otherwise, it returns 0, and the
contents of the array is undefined. (Thus at least since
libc 4.4.4; very old versions of libc, such as libc 4.4.1,
would return ''max'' if the array was too
small.)


Note that the return value 0 does not necessarily indicate
an error; for example, in many locales %p yields an empty
string.
!!ENVIRONMENT


The environment variables TZ and LC_TIME are
used.
!!CONFORMING TO


ANSI C, SVID 3, ISO 9899. There are strict inclusions
between the set of conversions given in ANSI C (unmarked),
those given in the Single Unix Specification (marked SU),
those given in Olson's timezone package (marked TZ), and
those given in glibc (marked GNU), except that %+ is not
supported in glibc2. On the other hand glibc2 has several
more extensions. POSIX.1 only refers to ANSI C; POSIX.2
describes under date(1) several extensions that could
apply to __strftime__ as well.
!!SEE ALSO


[date(1)], [time(2)], [ctime(3)],
[setlocale(3)], [sprintf(3)]
----
18 pages link to strftime(3):
This page is a man page (or other imported legacy content). We are unable to automatically determine the license status of this page.
Last edited on Friday, September 21, 2007 3:51:49 pm by IanMcDonald
Edit PageHistory Diff Info LikePages