279 lines
7.7 KiB
Groff
279 lines
7.7 KiB
Groff
.\" Copyright (c) 1989, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to Berkeley by
|
|
.\" the American National Standards Committee X3, on Information
|
|
.\" Processing Systems.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)strftime.3 8.1 (Berkeley) 6/4/93
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd November 4, 2004
|
|
.Dt STRFTIME 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm strftime
|
|
.Nd format date and time
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In time.h
|
|
.Ft size_t
|
|
.Fo strftime
|
|
.Fa "char * restrict buf"
|
|
.Fa "size_t maxsize"
|
|
.Fa "const char * restrict format"
|
|
.Fa "const struct tm * restrict timeptr"
|
|
.Fc
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn strftime
|
|
function formats the information from
|
|
.Fa timeptr
|
|
into the buffer
|
|
.Fa buf
|
|
according to the string pointed to by
|
|
.Fa format .
|
|
.Pp
|
|
The
|
|
.Fa 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
|
|
.Dq Ql %
|
|
and one other character.
|
|
.Pp
|
|
No more than
|
|
.Fa maxsize
|
|
characters will be placed into the array.
|
|
If the total number of resulting characters, including the terminating
|
|
NUL character, is not more than
|
|
.Fa maxsize ,
|
|
.Fn strftime
|
|
returns the number of characters in the array, not counting the
|
|
terminating NUL.
|
|
Otherwise, zero is returned and the buffer contents are indeterminate.
|
|
.Pp
|
|
The conversion specifications are copied to the buffer after expansion
|
|
as follows:-
|
|
.Bl -tag -width "xxxx"
|
|
.It Cm \&%A
|
|
is replaced by national representation of the full weekday name.
|
|
.It Cm %a
|
|
is replaced by national representation of
|
|
the abbreviated weekday name.
|
|
.It Cm \&%B
|
|
is replaced by national representation of the full month name.
|
|
.It Cm %b
|
|
is replaced by national representation of
|
|
the abbreviated month name.
|
|
.It Cm \&%C
|
|
is replaced by (year / 100) as decimal number; single
|
|
digits are preceded by a zero.
|
|
.It Cm %c
|
|
is replaced by national representation of time and date.
|
|
.It Cm \&%D
|
|
is equivalent to
|
|
.Dq Li %m/%d/%y .
|
|
.It Cm %d
|
|
is replaced by the day of the month as a decimal number (01-31).
|
|
.It Cm %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.
|
|
.Pp
|
|
Additionally %OB implemented
|
|
to represent alternative months names
|
|
(used standalone, without day mentioned).
|
|
.It Cm %e
|
|
is replaced by the day of the month as a decimal number (1-31); single
|
|
digits are preceded by a blank.
|
|
.It Cm \&%F
|
|
is equivalent to
|
|
.Dq Li %Y-%m-%d .
|
|
.It Cm \&%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).
|
|
.It Cm %g
|
|
is replaced by the same year as in
|
|
.Dq Li %G ,
|
|
but as a decimal number without century (00-99).
|
|
.It Cm \&%H
|
|
is replaced by the hour (24-hour clock) as a decimal number (00-23).
|
|
.It Cm %h
|
|
the same as
|
|
.Cm %b .
|
|
.It Cm \&%I
|
|
is replaced by the hour (12-hour clock) as a decimal number (01-12).
|
|
.It Cm %j
|
|
is replaced by the day of the year as a decimal number (001-366).
|
|
.It Cm %k
|
|
is replaced by the hour (24-hour clock) as a decimal number (0-23);
|
|
single digits are preceded by a blank.
|
|
.It Cm %l
|
|
is replaced by the hour (12-hour clock) as a decimal number (1-12);
|
|
single digits are preceded by a blank.
|
|
.It Cm \&%M
|
|
is replaced by the minute as a decimal number (00-59).
|
|
.It Cm %m
|
|
is replaced by the month as a decimal number (01-12).
|
|
.It Cm %n
|
|
is replaced by a newline.
|
|
.It Cm %O*
|
|
the same as
|
|
.Cm %E* .
|
|
.It Cm %p
|
|
is replaced by national representation of either
|
|
"ante meridiem"
|
|
or
|
|
"post meridiem"
|
|
as appropriate.
|
|
.It Cm \&%R
|
|
is equivalent to
|
|
.Dq Li %H:%M .
|
|
.It Cm %r
|
|
is equivalent to
|
|
.Dq Li %I:%M:%S %p .
|
|
.It Cm \&%S
|
|
is replaced by the second as a decimal number (00-60).
|
|
.It Cm %s
|
|
is replaced by the number of seconds since the Epoch, UTC (see
|
|
.Xr mktime 3 ) .
|
|
.It Cm \&%T
|
|
is equivalent to
|
|
.Dq Li %H:%M:%S .
|
|
.It Cm %t
|
|
is replaced by a tab.
|
|
.It Cm \&%U
|
|
is replaced by the week number of the year (Sunday as the first day of
|
|
the week) as a decimal number (00-53).
|
|
.It Cm %u
|
|
is replaced by the weekday (Monday as the first day of the week)
|
|
as a decimal number (1-7).
|
|
.It Cm \&%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.
|
|
.It Cm %v
|
|
is equivalent to
|
|
.Dq Li %e-%b-%Y .
|
|
.It Cm \&%W
|
|
is replaced by the week number of the year (Monday as the first day of
|
|
the week) as a decimal number (00-53).
|
|
.It Cm %w
|
|
is replaced by the weekday (Sunday as the first day of the week)
|
|
as a decimal number (0-6).
|
|
.It Cm \&%X
|
|
is replaced by national representation of the time.
|
|
.It Cm %x
|
|
is replaced by national representation of the date.
|
|
.It Cm \&%Y
|
|
is replaced by the year with century as a decimal number.
|
|
.It Cm %y
|
|
is replaced by the year without century as a decimal number (00-99).
|
|
.It Cm \&%Z
|
|
is replaced by the time zone name.
|
|
.It Cm %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).
|
|
.It Cm %+
|
|
is replaced by national representation of the date and time
|
|
(the format is similar to that produced by
|
|
.Xr date 1 ) .
|
|
.It Cm %-*
|
|
GNU libc extension.
|
|
Do not do any padding when performing numerical outputs.
|
|
.It Cm %_*
|
|
GNU libc extension.
|
|
Explicitly specify space for padding.
|
|
.It Cm %0*
|
|
GNU libc extension.
|
|
Explicitly specify zero for padding.
|
|
.It Cm %%
|
|
is replaced by
|
|
.Ql % .
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr date 1 ,
|
|
.Xr printf 1 ,
|
|
.Xr ctime 3 ,
|
|
.Xr printf 3 ,
|
|
.Xr strptime 3 ,
|
|
.Xr wcsftime 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn strftime
|
|
function
|
|
conforms to
|
|
.St -isoC
|
|
with a lot of extensions including
|
|
.Ql %C ,
|
|
.Ql \&%D ,
|
|
.Ql %E* ,
|
|
.Ql %e ,
|
|
.Ql %G ,
|
|
.Ql %g ,
|
|
.Ql %h ,
|
|
.Ql %k ,
|
|
.Ql %l ,
|
|
.Ql %n ,
|
|
.Ql %O* ,
|
|
.Ql \&%R ,
|
|
.Ql %r ,
|
|
.Ql %s ,
|
|
.Ql \&%T ,
|
|
.Ql %t ,
|
|
.Ql %u ,
|
|
.Ql \&%V ,
|
|
.Ql %z ,
|
|
.Ql %+ .
|
|
.Pp
|
|
The peculiar week number and year in the replacements of
|
|
.Ql %G ,
|
|
.Ql %g
|
|
and
|
|
.Ql \&%V
|
|
are defined in ISO 8601: 1988.
|
|
.Sh BUGS
|
|
There is no conversion specification for the phase of the moon.
|
|
.Pp
|
|
The
|
|
.Fn strftime
|
|
function does not correctly handle multibyte characters in the
|
|
.Fa format
|
|
argument.
|