b6cbf7203b
This patch imports the unmodified current version of NetBSD libc. The NetBSD includes are in /nbsd_include, while the libc code itself is split between lib/nbsd_libc and common/lib/libc.
265 lines
8.5 KiB
Groff
265 lines
8.5 KiB
Groff
.\" Copyright (c) 1989, 1991 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.
|
|
.\" 3. 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.
|
|
.\"
|
|
.\" from: @(#)strftime.3 5.12 (Berkeley) 6/29/91
|
|
.\" $NetBSD: strftime.3,v 1.27 2010/12/16 18:38:07 christos Exp $
|
|
.\"
|
|
.Dd December 14, 2010
|
|
.Dt STRFTIME 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm strftime ,
|
|
.Nm strftime_z
|
|
.Nd format date and time
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In time.h
|
|
.Ft size_t
|
|
.Fn strftime "char * restrict buf" "size_t maxsize" "const char * restrict format" "const struct tm * restrict timeptr"
|
|
.Ft size_t
|
|
.Fn strftime_z "const timezone_t tz" "char * restrict buf" "size_t maxsize" "const char * restrict format" "const struct tm * restrict timeptr"
|
|
.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
|
|
.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
|
|
null character, is not more than
|
|
.Fa maxsize ,
|
|
.Fn strftime
|
|
returns the number of characters in the array, not counting the
|
|
terminating null.
|
|
Otherwise, zero is returned and the contents of the array are undefined.
|
|
.Pp
|
|
Each conversion specification is replaced by the characters as
|
|
follows which are then copied into the buffer.
|
|
.Bl -tag -width "xxxx"
|
|
.It Cm \&%A
|
|
is replaced by the locale's full weekday name.
|
|
.It Cm %a
|
|
is replaced by the locale's abbreviated weekday name.
|
|
.It Cm \&%B
|
|
is replaced by the locale's full month name.
|
|
.It Cm \&%b No or Cm \&%h
|
|
is replaced by the locale's abbreviated month name.
|
|
.It Cm \&%C
|
|
is replaced by the century (a year divided by 100 and truncated to an integer)
|
|
as a decimal number [00,99].
|
|
.It Cm \&%c
|
|
is replaced by the locale's appropriate date and time representation.
|
|
.It Cm \&%D
|
|
is replaced by the date in the format
|
|
.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
|
|
is replaced by the day of month as a decimal number [1,31];
|
|
single digits are preceded by a blank.
|
|
.It Cm \&%F
|
|
is replaced by the date in the format
|
|
.Dq Li %Y-%m-%d
|
|
(the ISO 8601 date format).
|
|
.It Cm \&%G
|
|
is replaced by the ISO 8601 year with century as a decimal number.
|
|
.It Cm \&%g
|
|
is replaced by the ISO 8601 year without century as a decimal number (00-99).
|
|
This is the year that includes the greater part of the week.
|
|
(Monday as the first day of a week).
|
|
See also the
|
|
.Ql \&%V
|
|
conversion specification.
|
|
.It Cm \&%H
|
|
is replaced by the hour (24-hour clock) as a decimal number [00,23].
|
|
.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 %p
|
|
is replaced by the locale's equivalent of either
|
|
.Dq Tn AM
|
|
or
|
|
.Dq Tn PM .
|
|
.It Cm \&%R
|
|
is replaced by the time in the format
|
|
.Dq Li %H:%M .
|
|
.It Cm \&%r
|
|
is replaced by the locale's representation of 12-hour clock time
|
|
using AM/PM notation.
|
|
.It Cm \&%S
|
|
is replaced by the second as a decimal number [00,61].
|
|
The range of
|
|
seconds is (00-61) instead of (00-59) to allow for the periodic occurrence
|
|
of leap seconds and double leap seconds.
|
|
.It Cm %s
|
|
is replaced by the number of seconds since the Epoch, UTC (see
|
|
.Xr mktime 3 ) .
|
|
.It Cm \&%T
|
|
is replaced by the time in the format
|
|
.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]. According to ISO 8601 the week
|
|
containing January 1 is week 1 if it has four or more days in the new year,
|
|
otherwise it is week 53 of the previous year, and the next week is week 1.
|
|
The year is given by the
|
|
.Ql \&%G
|
|
conversion specification.
|
|
.It Cm \&%v
|
|
is replaced by the date in the format
|
|
.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 the locale's appropriate time representation.
|
|
.It Cm \&%x
|
|
is replaced by the locale's appropriate date representation.
|
|
.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 offset from ITC in the ISO 8601 format
|
|
.Dq Li [-]hhmm .
|
|
.It Cm %%
|
|
is replaced by
|
|
.Ql % .
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn strftime_z
|
|
function is similar to
|
|
.Fn strftime ,
|
|
but it also takes a
|
|
.Ft "const timezone_t"
|
|
.Fa tz
|
|
argument.
|
|
.Sh SEE ALSO
|
|
.Xr date 1 ,
|
|
.Xr printf 1 ,
|
|
.Xr ctime 3 ,
|
|
.Xr printf 3 ,
|
|
.Xr strptime 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn strftime
|
|
function
|
|
conforms to
|
|
.St -isoC-99 .
|
|
The
|
|
.Ql \&%C ,
|
|
.Ql \&%D ,
|
|
.Ql \&%e ,
|
|
.Ql \&%g ,
|
|
.Ql \&%G ,
|
|
.Ql \&%h ,
|
|
.Ql \&%k ,
|
|
.Ql \&%l ,
|
|
.Ql \&%n ,
|
|
.Ql \&%r ,
|
|
.Ql \&%R ,
|
|
.Ql \&%s ,
|
|
.Ql \&%t ,
|
|
.Ql \&%T ,
|
|
.Ql \&%u ,
|
|
.Ql \&%V ,
|
|
and
|
|
.Ql \&%v
|
|
conversion specifications are extensions.
|
|
.Pp
|
|
Use of the ISO 8601 conversions may produce non-intuitive results.
|
|
Week 01 of a year is per definition the first week which has the Thursday
|
|
in this year, which is equivalent to the week which contains the fourth
|
|
day of January.
|
|
In other words, the first week of a new year is the week which has the
|
|
majority of its days in the new year.
|
|
Week 01 might also contain days from the previous year and the week
|
|
before week 01 of a year is the last week (52 or 53) of the previous
|
|
year even if it contains days from the new year.
|
|
A week starts with Monday (day 1) and ends with Sunday (day 7).
|
|
For example, the first week of the year 1997 lasts from
|
|
1996-12-30 to 1997-01-05.
|
|
.Sh BUGS
|
|
There is no conversion specification for the phase of the moon.
|
|
.Pp
|
|
A return value of zero does not necessarily indicate an error.
|
|
If the resulting string is an empty string, the result value is
|
|
zero and it is not possible to distinguish between success and error.
|
|
For example, in many locales
|
|
.Cm \&%p
|
|
yields an empty string.
|
|
This problem can be avoided by inserting an extra space at the
|
|
beginning of the format string and then skipping over it or removing
|
|
it from the result.
|