1STRPTIME(3) Linux Programmer's Manual STRPTIME(3)
2
6 strptime - convert a string representation of time to a time tm struc‐
7 ture
8
10 #define _XOPEN_SOURCE /* glibc2 needs this */
11 #include <time.h>
12 char *strptime(const char *s, const char *format, struct tm *tm);
14
16 The strptime() function is the converse function to strftime() and con‐
17 verts the character string pointed to by s to values which are stored
18 in the tm structure pointed to by tm, using the format specified by
19 format. Here format is a character string that consists of field
20 descriptors and text characters, reminiscent of scanf(3). Each field
21 descriptor consists of a % character followed by another character that
22 specifies the replacement for the field descriptor. All other charac‐
23 ters in the format string must have a matching character in the input
24 string, except for whitespace, which matches zero or more whitespace
25 characters in the input string. There should be whitespace or other
26 alphanumeric characters between any two field descriptors.
27 The strptime() function processes the input string from left to right.
29 Each of the three possible input elements (whitespace, literal, or for‐
30 mat) are handled one after the other. If the input cannot be matched
31 to the format string the function stops. The remainder of the format
32 and input strings are not processed.
33 The supported input field descriptors are listed below. In case a text
35 string (such as a weekday or month name) is to be matched, the compari‐
36 son is case insensitive. In case a number is to be matched, leading
37 zeros are permitted but not required.
38 %% The % character.
40 %a or %A
42 The weekday name according to the current locale, in abbreviated
43 form or the full name.
44 %b or %B or %h
46 The month name according to the current locale, in abbreviated
47 form or the full name.
48 %c The date and time representation for the current locale.
50 %C The century number (0-99).
52 %d or %e
54 The day of month (1-31).
55 %D Equivalent to %m/%d/%y. (This is the American style date, very
57 confusing to non-Americans, especially since %d/%m/%y is widely
58 used in Europe. The ISO 8601 standard format is %Y-%m-%d.)
59 %H The hour (0-23).
61 %I The hour on a 12-hour clock (1-12).
63 %j The day number in the year (1-366).
65 %m The month number (1-12).
67 %M The minute (0-59).
69 %n Arbitrary whitespace.
71 %p The locale's equivalent of AM or PM. (Note: there may be none.)
73 %r The 12-hour clock time (using the locale's AM or PM). In the
75 POSIX locale equivalent to %I:%M:%S %p. If t_fmt_ampm is empty
76 in the LC_TIME part of the current locale then the behaviour is
77 undefined.
78 %R Equivalent to %H:%M.
80 %S The second (0-60; 60 may occur for leap seconds; earlier also 61
82 was allowed).
83 %t Arbitrary whitespace.
85 %T Equivalent to %H:%M:%S.
87 %U The week number with Sunday the first day of the week (0-53).
89 The first Sunday of January is the first day of week 1.
90 %w The weekday number (0-6) with Sunday = 0.
92 %W The week number with Monday the first day of the week (0-53).
94 The first Monday of January is the first day of week 1.
95 %x The date, using the locale's date format.
97 %X The time, using the locale's time format.
99 %y The year within century (0-99). When a century is not otherwise
101 specified, values in the range 69-99 refer to years in the twen‐
102 tieth century (1969-1999); values in the range 00-68 refer to
103 years in the twenty-first century (2000-2068).
104 %Y The year, including century (for example, 1991).
106 Some field descriptors can be modified by the E or O modifier charac‐
108 ters to indicate that an alternative format or specification should be
109 used. If the alternative format or specification does not exist in the
110 current locale, the unmodified field descriptor is used.
111 The E modifier specifies that the input string may contain alternative
113 locale-dependent versions of the date and time representation:
114 %Ec The locale's alternative date and time representation.
116 %EC The name of the base year (period) in the locale's alternative
118 representation.
119 %Ex The locale's alternative date representation.
121 %EX The locale's alternative time representation.
123 %Ey The offset from %EC (year only) in the locale's alternative rep‐
125 resentation.
126 %EY The full alternative year representation.
128 The O modifier specifies that the numerical input may be in an alterna‐
130 tive locale-dependent format:
131 %Od or %Oe
133 The day of the month using the locale's alternative numeric sym‐
134 bols; leading zeros are permitted but not required.
135 %OH The hour (24-hour clock) using the locale's alternative numeric
137 symbols.
138 %OI The hour (12-hour clock) using the locale's alternative numeric
140 symbols.
141 %Om The month using the locale's alternative numeric symbols.
143 %OM The minutes using the locale's alternative numeric symbols.
145 %OS The seconds using the locale's alternative numeric symbols.
147 %OU The week number of the year (Sunday as the first day of the
149 week) using the locale's alternative numeric symbols.
150 %Ow The number of the weekday (Sunday=0) using the locale's alterna‐
152 tive numeric symbols.
153 %OW The week number of the year (Monday as the first day of the
155 week) using the locale's alternative numeric symbols.
156 %Oy The year (offset from %C) using the locale's alternative numeric
158 symbols.
159 The broken-down time structure tm is defined in <time.h> as follows:
161 struct tm {
163 int tm_sec; /* seconds */
164 int tm_min; /* minutes */
165 int tm_hour; /* hours */
166 int tm_mday; /* day of the month */
167 int tm_mon; /* month */
168 int tm_year; /* year */
169 int tm_wday; /* day of the week */
170 int tm_yday; /* day in the year */
171 int tm_isdst; /* daylight saving time */
172 };
173
175 The return value of the function is a pointer to the first character
176 not processed in this function call. In case the input string contains
177 more characters than required by the format string the return value
178 points right after the last consumed input character. In case the
179 whole input string is consumed the return value points to the null byte
180 at the end of the string. If strptime() fails to match all of the for‐
181 mat string and therefore an error occurred the function returns NULL.
182
184 SUSv2, POSIX.1-2001.
185
187 The following example demonstrates the use of strptime() and strf‐
188 time().
189 #include <stdio.h>
191 #include <time.h>
192 int main() {
194 struct tm tm;
195 char buf[255];
196 strptime("2001-11-12 18:31:01", "%Y-%m-%d %H:%M:%S", &tm);
198 strftime(buf, sizeof(buf), "%d %b %Y %H:%M", &tm);
199 puts(buf);
200 return 0;
201 }
202
204 For reasons of symmetry, glibc tries to support for strptime() the same
205 format characters as for strftime(). (In most cases the corresponding
206 fields are parsed, but no field in tm is changed.) This leads to
207 %F Equivalent to %Y-%m-%d, the ISO 8601 date format.
209 %g The year corresponding to the ISO week number, but without the
211 century (0-99).
212 %G The year corresponding to the ISO week number. (For example,
214 1991.)
215 %u The day of the week as a decimal number (1-7, where Monday = 1).
217 %V The ISO 8601:1988 week number as a decimal number (1-53). If
219 the week (starting on Monday) containing 1 January has four or
220 more days in the new year, then it is considered week 1. Other‐
221 wise, it is the last week of the previous year, and the next
222 week is week 1.
223 %z An RFC-822/ISO 8601 standard time zone specification.
225 %Z The timezone name.
227 Similarly, because of GNU extensions to strftime(), %k is accepted as a
229 synonym for %H, and %l should be accepted as a synonym for %I, and %P
230 is accepted as a synonym for %p. Finally
231 %s The number of seconds since the epoch, i.e., since 1970-01-01
233 00:00:00 UTC. Leap seconds are not counted unless leap second
234 support is available.
235 The GNU libc implementation does not require whitespace between two
237 field descriptors.
238
240 In principle, this function does not initialize tm but only stores the
241 values specified. This means that tm should be initialized before the
242 call. Details differ a bit between different Unix systems. The GNU
243 libc implementation does not touch those fields which are not explic‐
244 itly specified, except that it recomputes the tm_wday and tm_yday field
245 if any of the year, month, or day elements changed.
246 This function is available since libc 4.6.8. Linux libc4 and libc5
248 includes define the prototype unconditionally; glibc2 includes provide
249 a prototype only when _XOPEN_SOURCE or _GNU_SOURCE are defined.
250 Before libc 5.4.13 whitespace (and the 'n' and 't' specifications) was
252 not handled, no 'E' and 'O' locale modifier characters were accepted,
253 and the 'C' specification was a synonym for the 'c' specification.
254 The 'y' (year in century) specification is taken to specify a year in
256 the 20th century by libc4 and libc5. It is taken to be a year in the
257 range 1950-2049 by glibc 2.0. It is taken to be a year in 1969-2068
258 since glibc 2.1.
259
261 time(2), getdate(3), scanf(3), setlocale(3), strftime(3), fea‐
262 ture_test_macros(7)
263GNU 2001-11-12 STRPTIME(3)