xref: /freebsd/lib/libc/stdtime/strptime.3 (revision 2f02600abfddfc4e9f20dd384a2e729b451e16bd)
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26.\" $FreeBSD$
27.\" "
28.Dd June 25, 2012
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).
83.Pp
84If the
85.Fa format
86string does not contain enough conversion specifications to completely
87specify the resulting
88.Vt struct tm ,
89the unspecified members of
90.Va timeptr
91are left untouched.
92For example, if
93.Fa format
94is
95.Dq Li "%H:%M:%S" ,
96only
97.Va tm_hour ,
98.Va tm_sec
99and
100.Va tm_min
101will be modified.
102If time relative to today is desired, initialize the
103.Fa timeptr
104structure with today's date before passing it to
105.Fn strptime .
106.Sh RETURN VALUES
107Upon successful completion,
108.Fn strptime
109returns the pointer to the first character in
110.Fa buf
111that has not been required to satisfy the specified conversions in
112.Fa format .
113It returns
114.Dv NULL
115if one of the conversions failed.
116.Fn strptime_l
117returns the same values as
118.Fn strptime .
119.Sh SEE ALSO
120.Xr date 1 ,
121.Xr scanf 3 ,
122.Xr strftime 3
123.Sh HISTORY
124The
125.Fn strptime
126function appeared in
127.Fx 3.0 .
128.Sh AUTHORS
129The
130.Fn strptime
131function has been contributed by Powerdog Industries.
132.Pp
133This man page was written by
134.An J\(:org Wunsch .
135.Sh BUGS
136Both the
137.Fa %e
138and
139.Fa %l
140format specifiers may incorrectly scan one too many digits
141if the intended values comprise only a single digit
142and that digit is followed immediately by another digit.
143Both specifiers accept zero-padded values,
144even though they are both defined as taking unpadded values.
145.Pp
146The
147.Fa %p
148format specifier has no effect unless it is parsed
149.Em after
150hour-related specifiers.
151Specifying
152.Fa %l
153without
154.Fa %p
155will produce undefined results.
156Note that 12AM
157(ante meridiem)
158is taken as midnight
159and 12PM
160(post meridiem)
161is taken as noon.
162.Pp
163The
164.Fa \&%U
165and
166.Fa %W
167format specifiers accept any value within the range 00 to 53
168without validating against other values supplied (like month
169or day of the year, for example).
170.Pp
171The
172.Fa %Z
173format specifier only accepts time zone abbreviations of the local time zone,
174or the value "GMT".
175This limitation is because of ambiguity due to of the over loading of time
176zone abbreviations.
177One such example is
178.Fa EST
179which is both Eastern Standard Time and Eastern Australia Summer Time.
180.Pp
181The
182.Fn strptime
183function does not correctly handle multibyte characters in the
184.Fa format
185argument.
186