xref: /freebsd/lib/libc/stdtime/strptime.3 (revision 3416500aef140042c64bc149cb1ec6620483bc44)
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26.\" $FreeBSD$
27.\" "
28.Dd October 2, 2014
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.In time.h
45.In xlocale.h
46.Ft char *
47.Fn strptime_l "const char * restrict buf" "const char * restrict format" "struct tm * restrict timeptr" "locale_t loc"
48.Sh DESCRIPTION
49The
50.Fn strptime
51function parses the string in the buffer
52.Fa buf
53according to the string pointed to by
54.Fa format ,
55and fills in the elements of the structure pointed to by
56.Fa timeptr .
57The resulting values will be relative to the local time zone.
58Thus, it can be considered the reverse operation of
59.Xr strftime 3 .
60The
61.Fn strptime_l
62function does the same as
63.Fn strptime ,
64but takes an explicit locale rather than using the current locale.
65.Pp
66The
67.Fa format
68string consists of zero or more conversion specifications and
69ordinary characters.
70All ordinary characters are matched exactly with the buffer, where
71white space in the format string will match any amount of white space
72in the buffer.
73All conversion specifications are identical to those described in
74.Xr strftime 3 .
75.Pp
76Two-digit year values, including formats
77.Fa %y
78and
79.Fa \&%D ,
80are now interpreted as beginning at 1969 per POSIX requirements.
81Years 69-00 are interpreted in the 20th century (1969-2000), years
8201-68 in the 21st century (2001-2068).
83The
84.Fa \&%U
85and
86.Fa %W
87format specifiers accept any value within the range 00 to 53.
88.Pp
89If the
90.Fa format
91string does not contain enough conversion specifications to completely
92specify the resulting
93.Vt struct tm ,
94the unspecified members of
95.Va timeptr
96are left untouched.
97For example, if
98.Fa format
99is
100.Dq Li "%H:%M:%S" ,
101only
102.Va tm_hour ,
103.Va tm_sec
104and
105.Va tm_min
106will be modified.
107If time relative to today is desired, initialize the
108.Fa timeptr
109structure with today's date before passing it to
110.Fn strptime .
111.Sh RETURN VALUES
112Upon successful completion,
113.Fn strptime
114returns the pointer to the first character in
115.Fa buf
116that has not been required to satisfy the specified conversions in
117.Fa format .
118It returns
119.Dv NULL
120if one of the conversions failed.
121.Fn strptime_l
122returns the same values as
123.Fn strptime .
124.Sh SEE ALSO
125.Xr date 1 ,
126.Xr scanf 3 ,
127.Xr strftime 3
128.Sh HISTORY
129The
130.Fn strptime
131function appeared in
132.Fx 3.0 .
133.Sh AUTHORS
134The
135.Fn strptime
136function has been contributed by Powerdog Industries.
137.Pp
138This man page was written by
139.An J\(:org Wunsch .
140.Sh BUGS
141Both the
142.Fa %e
143and
144.Fa %l
145format specifiers may incorrectly scan one too many digits
146if the intended values comprise only a single digit
147and that digit is followed immediately by another digit.
148Both specifiers accept zero-padded values,
149even though they are both defined as taking unpadded values.
150.Pp
151The
152.Fa %p
153format specifier has no effect unless it is parsed
154.Em after
155hour-related specifiers.
156Specifying
157.Fa %l
158without
159.Fa %p
160will produce undefined results.
161Note that 12AM
162(ante meridiem)
163is taken as midnight
164and 12PM
165(post meridiem)
166is taken as noon.
167.Pp
168The
169.Fa %Z
170format specifier only accepts time zone abbreviations of the local time zone,
171or the value "GMT".
172This limitation is because of ambiguity due to of the over loading of time
173zone abbreviations.
174One such example is
175.Fa EST
176which is both Eastern Standard Time and Eastern Australia Summer Time.
177.Pp
178The
179.Fn strptime
180function does not correctly handle multibyte characters in the
181.Fa format
182argument.
183