xref: /freebsd/lib/libc/stdtime/strptime.3 (revision a2f733abcff64628b7771a47089628b7327a88bd)
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26.Dd October 2, 2014
27.Dt STRPTIME 3
28.Os
29.Sh NAME
30.Nm strptime
31.Nd parse date and time string
32.Sh LIBRARY
33.Lb libc
34.Sh SYNOPSIS
35.In time.h
36.Ft char *
37.Fo strptime
38.Fa "const char * restrict buf"
39.Fa "const char * restrict format"
40.Fa "struct tm * restrict timeptr"
41.Fc
42.In time.h
43.In xlocale.h
44.Ft char *
45.Fn strptime_l "const char * restrict buf" "const char * restrict format" "struct tm * restrict timeptr" "locale_t loc"
46.Sh DESCRIPTION
47The
48.Fn strptime
49function parses the string in the buffer
50.Fa buf
51according to the string pointed to by
52.Fa format ,
53and fills in the elements of the structure pointed to by
54.Fa timeptr .
55The resulting values will be relative to the local time zone.
56Thus, it can be considered the reverse operation of
57.Xr strftime 3 .
58The
59.Fn strptime_l
60function does the same as
61.Fn strptime ,
62but takes an explicit locale rather than using the current locale.
63.Pp
64The
65.Fa format
66string consists of zero or more conversion specifications and
67ordinary characters.
68All ordinary characters are matched exactly with the buffer, where
69white space in the format string will match any amount of white space
70in the buffer.
71All conversion specifications are identical to those described in
72.Xr strftime 3 .
73.Pp
74Two-digit year values, including formats
75.Fa %y
76and
77.Fa \&%D ,
78are now interpreted as beginning at 1969 per POSIX requirements.
79Years 69-00 are interpreted in the 20th century (1969-2000), years
8001-68 in the 21st century (2001-2068).
81The
82.Fa \&%U
83and
84.Fa %W
85format specifiers accept any value within the range 00 to 53.
86.Pp
87If the
88.Fa format
89string does not contain enough conversion specifications to completely
90specify the resulting
91.Vt struct tm ,
92the unspecified members of
93.Va timeptr
94are left untouched.
95For example, if
96.Fa format
97is
98.Dq Li "%H:%M:%S" ,
99only
100.Va tm_hour ,
101.Va tm_sec
102and
103.Va tm_min
104will be modified.
105If time relative to today is desired, initialize the
106.Fa timeptr
107structure with today's date before passing it to
108.Fn strptime .
109.Sh RETURN VALUES
110Upon successful completion,
111.Fn strptime
112returns the pointer to the first character in
113.Fa buf
114that has not been required to satisfy the specified conversions in
115.Fa format .
116It returns
117.Dv NULL
118if one of the conversions failed.
119.Fn strptime_l
120returns the same values as
121.Fn strptime .
122.Sh SEE ALSO
123.Xr date 1 ,
124.Xr scanf 3 ,
125.Xr strftime 3
126.Sh HISTORY
127The
128.Fn strptime
129function appeared in
130.Fx 3.0 .
131.Sh AUTHORS
132The
133.Fn strptime
134function has been contributed by Powerdog Industries.
135.Pp
136This man page was written by
137.An J\(:org Wunsch .
138.Sh BUGS
139Both the
140.Fa %e
141and
142.Fa %l
143format specifiers may incorrectly scan one too many digits
144if the intended values comprise only a single digit
145and that digit is followed immediately by another digit.
146Both specifiers accept zero-padded values,
147even though they are both defined as taking unpadded values.
148.Pp
149The
150.Fa %p
151format specifier has no effect unless it is parsed
152.Em after
153hour-related specifiers.
154Specifying
155.Fa %l
156without
157.Fa %p
158will produce undefined results.
159Note that 12AM
160(ante meridiem)
161is taken as midnight
162and 12PM
163(post meridiem)
164is taken as noon.
165.Pp
166The
167.Fa %Z
168format specifier only accepts time zone abbreviations of the local time zone,
169or the value "GMT".
170This limitation is because of ambiguity due to of the over loading of time
171zone abbreviations.
172One such example is
173.Fa EST
174which is both Eastern Standard Time and Eastern Australia Summer Time.
175.Pp
176The
177.Fn strptime
178function does not correctly handle multibyte characters in the
179.Fa format
180argument.
181