xref: /freebsd/lib/libc/stdtime/strptime.3 (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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26.\" $FreeBSD$
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
45The
46.Fn strptime
47function parses the string in the buffer
48.Fa buf
49according to the string pointed to by
50.Fa format ,
51and fills in the elements of the structure pointed to by
52.Fa timeptr .
53The resulting values will be relative to the local time zone.
54Thus, it can be considered the reverse operation of
55.Xr strftime 3 .
56.Pp
57The
58.Fa format
59string consists of zero or more conversion specifications and
60ordinary characters.
61All ordinary characters are matched exactly with the buffer, where
62white space in the format string will match any amount of white space
63in the buffer.
64All conversion specifications are identical to those described in
65.Xr strftime 3 .
66.Pp
67Two-digit year values, including formats
68.Fa %y
69and
70.Fa \&%D ,
71are now interpreted as beginning at 1969 per POSIX requirements.
72Years 69-00 are interpreted in the 20th century (1969-2000), years
7301-68 in the 21st century (2001-2068).
74.Pp
75If the
76.Fa format
77string does not contain enough conversion specifications to completely
78specify the resulting
79.Vt struct tm ,
80the unspecified members of
81.Va timeptr
82are left untouched.
83For example, if
84.Fa format
85is
86.Dq Li "%H:%M:%S" ,
87only
88.Va tm_hour ,
89.Va tm_sec
90and
91.Va tm_min
92will be modified.
93If time relative to today is desired, initialize the
94.Fa timeptr
95structure with today's date before passing it to
96.Fn strptime .
97.Sh RETURN VALUES
98Upon successful completion,
99.Fn strptime
100returns the pointer to the first character in
101.Fa buf
102that has not been required to satisfy the specified conversions in
103.Fa format .
104It returns
105.Dv NULL
106if one of the conversions failed.
107.Sh SEE ALSO
108.Xr date 1 ,
109.Xr scanf 3 ,
110.Xr strftime 3
111.Sh HISTORY
112The
113.Fn strptime
114function appeared in
115.Fx 3.0 .
116.Sh AUTHORS
117The
118.Fn strptime
119function has been contributed by Powerdog Industries.
120.Pp
121This man page was written by
122.An J\(:org Wunsch .
123.Sh BUGS
124Both the
125.Fa %e
126and
127.Fa %l
128format specifiers may incorrectly scan one too many digits
129if the intended values comprise only a single digit
130and that digit is followed immediately by another digit.
131Both specifiers accept zero-padded values,
132even though they are both defined as taking unpadded values.
133.Pp
134The
135.Fa %p
136format specifier has no effect unless it is parsed
137.Em after
138hour-related specifiers.
139Specifying
140.Fa %l
141without
142.Fa %p
143will produce undefined results.
144Note that 12AM
145(ante meridiem)
146is taken as midnight
147and 12PM
148(post meridiem)
149is taken as noon.
150.Pp
151The
152.Fa %U
153and
154.Fa %W
155format specifiers accept any value within the range 00 to 53
156without validating against other values supplied (like month
157or day of the year, for example).
158.Pp
159The
160.Fa %Z
161format specifier only accepts time zone abbreviations of the local time zone,
162or the value "GMT".
163This limitation is because of ambiguity due to of the over loading of time
164zone abbreviations.
165One such example is
166.Fa EST
167which is both Eastern Standard Time and Eastern Australia Summer Time.
168.Pp
169The
170.Fn strptime
171function does not correctly handle multibyte characters in the
172.Fa format
173argument.
174