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	1	.\"
	2	.\" Copyright (c) 1997 Joerg Wunsch
	3	.\"
	4	.\" All rights reserved.
	5	.\"
	6	.\" Redistribution and use in source and binary forms, with or without
	7	.\" modification, are permitted provided that the following conditions
	8	.\" are met:
	9	.\" 1. Redistributions of source code must retain the above copyright
	10	.\" notice, this list of conditions and the following disclaimer.
	11	.\" 2. Redistributions in binary form must reproduce the above copyright
	12	.\" notice, this list of conditions and the following disclaimer in the
	13	.\" documentation and/or other materials provided with the distribution.
	14	.\"
	15	.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
	16	.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	17	.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	18	.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
	19	.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	20	.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	21	.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	22	.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	23	.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	24	.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	25	.\"
	26	.\" $FreeBSD: src/lib/libc/stdtime/strptime.3,v 1.23 2004/07/02 23:52:12 ru Exp $
	27	.\" "
	28	.Dd January 4, 2003
	29	.Dt STRPTIME 3
	30	.Os
	31	.Sh NAME
	32	.Nm strptime
	33	.Nd parse date and time string
	34	.Sh LIBRARY
	35	.Lb libc
	36	.Sh SYNOPSIS
	37	.In time.h
	38	.Ft char *
	39	.Fo strptime
	40	.Fa "const char * restrict buf"
	41	.Fa "const char * restrict format"
	42	.Fa "struct tm * restrict timeptr"
	43	.Fc
	44	.Sh DESCRIPTION
	45	The
	46	.Fn strptime
	47	function parses the string in the buffer
	48	.Fa buf
	49	according to the string pointed to by
	50	.Fa format ,
	51	and fills in the elements of the structure pointed to by
	52	.Fa timeptr .
	53	The resulting values will be relative to the local time zone.
	54	Thus, it can be considered the reverse operation of
	55	.Xr strftime 3 .
	56	.Pp
	57	The
	58	.Fa format
	59	string consists of zero or more conversion specifications and
	60	ordinary characters.
	61	All ordinary characters are matched exactly with the buffer, where
	62	white space in the format string will match any amount of white space
	63	in the buffer.
	64	All conversion specifications are identical to those described in
	65	.Xr strftime 3 .
	66	.Pp
	67	Two-digit year values, including formats
	68	.Fa %y
	69	and
	70	.Fa \&%D ,
	71	are now interpreted as beginning at 1969 per POSIX requirements.
	72	Years 69-00 are interpreted in the 20th century (1969-2000), years
	73	01-68 in the 21st century (2001-2068).
	74	.Pp
	75	If the
	76	.Fa format
	77	string does not contain enough conversion specifications to completely
	78	specify the resulting
	79	.Vt struct tm ,
	80	the unspecified members of
	81	.Va timeptr
	82	are left untouched.
	83	For example, if
	84	.Fa format
	85	is
	86	.Dq Li "%H:%M:%S" ,
	87	only
	88	.Va tm_hour ,
	89	.Va tm_sec
	90	and
	91	.Va tm_min
	92	will be modified.
	93	If time relative to today is desired, initialize the
	94	.Fa timeptr
	95	structure with today's date before passing it to
	96	.Fn strptime .
	97	.Sh RETURN VALUES
	98	Upon successful completion,
	99	.Fn strptime
	100	returns the pointer to the first character in
	101	.Fa buf
	102	that has not been required to satisfy the specified conversions in
	103	.Fa format .
	104	It returns
	105	.Dv NULL
	106	if one of the conversions failed.
	107	.Sh SEE ALSO
	108	.Xr date 1 ,
	109	.Xr scanf 3 ,
	110	.Xr strftime 3
	111	.Sh AUTHORS
	112	The
	113	.Fn strptime
	114	function has been contributed by Powerdog Industries.
	115	.Pp
	116	This man page was written by
	117	.An J\(:org Wunsch .
	118	.Sh HISTORY
	119	The
	120	.Fn strptime
	121	function appeared in
	122	.Fx 3.0 .
	123	.Sh BUGS
	124	Both the
	125	.Fa %e
	126	and
	127	.Fa %l
	128	format specifiers may incorrectly scan one too many digits
	129	if the intended values comprise only a single digit
	130	and that digit is followed immediately by another digit.
	131	Both specifiers accept zero-padded values,
	132	even though they are both defined as taking unpadded values.
	133	.Pp
	134	The
	135	.Fa %p
	136	format specifier has no effect unless it is parsed
	137	.Em after
	138	hour-related specifiers.
	139	Specifying
	140	.Fa %l
	141	without
	142	.Fa %p
	143	will produce undefined results.
	144	Note that 12AM
	145	(ante meridiem)
	146	is taken as midnight
	147	and 12PM
	148	(post meridiem)
	149	is taken as noon.
	150	.Pp
	151	The
	152	.Fa %U
	153	and
	154	.Fa %W
	155	format specifiers accept any value within the range 00 to 53
	156	without validating against other values supplied (like month
	157	or day of the year, for example).
	158	.Pp
	159	The
	160	.Fa %Z
	161	format specifier only accepts time zone abbreviations of the local time zone,
	162	or the value "GMT".
	163	This limitation is because of ambiguity due to of the over loading of time
	164	zone abbreviations.
	165	One such example is
	166	.Fa EST
	167	which is both Eastern Standard Time and Eastern Australia Summer Time.
	168	.Pp
	169	The
	170	.Fn strptime
	171	function does not correctly handle multibyte characters in the
	172	.Fa format
	173	argument.