1STRPTIME(3)                Linux Programmer's Manual               STRPTIME(3)
2
3
4

NAME

6       strptime  - convert a string representation of time to a time tm struc‐
7       ture
8

SYNOPSIS

10       #define _XOPEN_SOURCE       /* See feature_test_macros(7) */
11       #include <time.h>
12
13       char *strptime(const char *restrict s, const char *restrict format,
14                      struct tm *restrict tm);
15

DESCRIPTION

17       The strptime() function is the converse of strftime(3); it converts the
18       character  string  pointed  to  by  s to values which are stored in the
19       "broken-down time" structure pointed to by tm, using the format  speci‐
20       fied by format.
21
22       The broken-down time structure tm is defined in <time.h> as follows:
23
24           struct tm {
25               int tm_sec;    /* Seconds (0-60) */
26               int tm_min;    /* Minutes (0-59) */
27               int tm_hour;   /* Hours (0-23) */
28               int tm_mday;   /* Day of the month (1-31) */
29               int tm_mon;    /* Month (0-11) */
30               int tm_year;   /* Year - 1900 */
31               int tm_wday;   /* Day of the week (0-6, Sunday = 0) */
32               int tm_yday;   /* Day in the year (0-365, 1 Jan = 0) */
33               int tm_isdst;  /* Daylight saving time */
34           };
35
36       For more details on the tm structure, see ctime(3).
37
38       The  format  argument  is a character string that consists of field de‐
39       scriptors and text characters, reminiscent of scanf(3).  Each field de‐
40       scriptor  consists  of a % character followed by another character that
41       specifies the replacement for the field descriptor.  All other  charac‐
42       ters  in  the format string must have a matching character in the input
43       string, except for whitespace, which matches zero  or  more  whitespace
44       characters  in  the  input string.  There should be whitespace or other
45       alphanumeric characters between any two field descriptors.
46
47       The strptime() function processes the input string from left to  right.
48       Each of the three possible input elements (whitespace, literal, or for‐
49       mat) are handled one after the other.  If the input cannot  be  matched
50       to  the format string, the function stops.  The remainder of the format
51       and input strings are not processed.
52
53       The supported input field descriptors are listed below.  In case a text
54       string (such as the name of a day of the week or a month name) is to be
55       matched, the comparison is case insensitive.  In case a number is to be
56       matched, leading zeros are permitted but not required.
57
58       %%     The % character.
59
60       %a or %A
61              The name of the day of the week according to the current locale,
62              in abbreviated form or the full name.
63
64       %b or %B or %h
65              The month name according to the current locale,  in  abbreviated
66              form or the full name.
67
68       %c     The date and time representation for the current locale.
69
70       %C     The century number (0–99).
71
72       %d or %e
73              The day of month (1–31).
74
75       %D     Equivalent  to %m/%d/%y.  (This is the American style date, very
76              confusing to non-Americans, especially since %d/%m/%y is  widely
77              used in Europe.  The ISO 8601 standard format is %Y-%m-%d.)
78
79       %H     The hour (0–23).
80
81       %I     The hour on a 12-hour clock (1–12).
82
83       %j     The day number in the year (1–366).
84
85       %m     The month number (1–12).
86
87       %M     The minute (0–59).
88
89       %n     Arbitrary whitespace.
90
91       %p     The locale's equivalent of AM or PM.  (Note: there may be none.)
92
93       %r     The  12-hour  clock  time (using the locale's AM or PM).  In the
94              POSIX locale equivalent to %I:%M:%S %p.  If t_fmt_ampm is  empty
95              in  the LC_TIME part of the current locale, then the behavior is
96              undefined.
97
98       %R     Equivalent to %H:%M.
99
100       %S     The second (0–60; 60 may occur for leap seconds; earlier also 61
101              was allowed).
102
103       %t     Arbitrary whitespace.
104
105       %T     Equivalent to %H:%M:%S.
106
107       %U     The  week  number  with Sunday the first day of the week (0–53).
108              The first Sunday of January is the first day of week 1.
109
110       %w     The ordinal number of the day of the week (0–6), with  Sunday  =
111              0.
112
113       %W     The  week  number  with Monday the first day of the week (0–53).
114              The first Monday of January is the first day of week 1.
115
116       %x     The date, using the locale's date format.
117
118       %X     The time, using the locale's time format.
119
120       %y     The year within century (0–99).  When a century is not otherwise
121              specified, values in the range 69–99 refer to years in the twen‐
122              tieth century (1969–1999); values in the range  00–68  refer  to
123              years in the twenty-first century (2000–2068).
124
125       %Y     The year, including century (for example, 1991).
126
127       Some  field  descriptors can be modified by the E or O modifier charac‐
128       ters to indicate that an alternative format or specification should  be
129       used.  If the alternative format or specification does not exist in the
130       current locale, the unmodified field descriptor is used.
131
132       The E modifier specifies that the input string may contain  alternative
133       locale-dependent versions of the date and time representation:
134
135       %Ec    The locale's alternative date and time representation.
136
137       %EC    The  name  of the base year (period) in the locale's alternative
138              representation.
139
140       %Ex    The locale's alternative date representation.
141
142       %EX    The locale's alternative time representation.
143
144       %Ey    The offset from %EC (year only) in the locale's alternative rep‐
145              resentation.
146
147       %EY    The full alternative year representation.
148
149       The O modifier specifies that the numerical input may be in an alterna‐
150       tive locale-dependent format:
151
152       %Od or %Oe
153              The day of the month using the locale's alternative numeric sym‐
154              bols; leading zeros are permitted but not required.
155
156       %OH    The  hour (24-hour clock) using the locale's alternative numeric
157              symbols.
158
159       %OI    The hour (12-hour clock) using the locale's alternative  numeric
160              symbols.
161
162       %Om    The month using the locale's alternative numeric symbols.
163
164       %OM    The minutes using the locale's alternative numeric symbols.
165
166       %OS    The seconds using the locale's alternative numeric symbols.
167
168       %OU    The  week  number  of  the  year (Sunday as the first day of the
169              week) using the locale's alternative numeric symbols.
170
171       %Ow    The ordinal number of the day of the week (Sunday=0),
172               using the locale's alternative numeric symbols.
173
174       %OW    The week number of the year (Monday as  the  first  day  of  the
175              week) using the locale's alternative numeric symbols.
176
177       %Oy    The year (offset from %C) using the locale's alternative numeric
178              symbols.
179

RETURN VALUE

181       The return value of the function is a pointer to  the  first  character
182       not processed in this function call.  In case the input string contains
183       more characters than required by the format string,  the  return  value
184       points  right  after  the  last  consumed input character.  In case the
185       whole input string is consumed, the return value  points  to  the  null
186       byte at the end of the string.  If strptime() fails to match all of the
187       format string and therefore an error  occurred,  the  function  returns
188       NULL.
189

ATTRIBUTES

191       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
192       tributes(7).
193
194       ┌─────────────────────────────────┬───────────────┬────────────────────┐
195Interface                        Attribute     Value              
196       ├─────────────────────────────────┼───────────────┼────────────────────┤
197strptime()                       │ Thread safety │ MT-Safe env locale │
198       └─────────────────────────────────┴───────────────┴────────────────────┘
199

CONFORMING TO

201       POSIX.1-2001, POSIX.1-2008, SUSv2.
202

NOTES

204       In principle, this function does not initialize tm but stores only  the
205       values  specified.  This means that tm should be initialized before the
206       call.  Details differ a bit between different UNIX systems.  The  glibc
207       implementation  does  not  touch  those fields which are not explicitly
208       specified, except that it recomputes the tm_wday and tm_yday  field  if
209       any of the year, month, or day elements changed.
210
211       The  'y'  (year in century) specification is taken to specify a year in
212       the range 1950–2049 by glibc  2.0.   It  is  taken  to  be  a  year  in
213       1969–2068 since glibc 2.1.
214
215   Glibc notes
216       For reasons of symmetry, glibc tries to support for strptime() the same
217       format characters as for strftime(3).  (In most cases, the  correspond‐
218       ing fields are parsed, but no field in tm is changed.)  This leads to
219
220       %F     Equivalent to %Y-%m-%d, the ISO 8601 date format.
221
222       %g     The  year  corresponding to the ISO week number, but without the
223              century (0–99).
224
225       %G     The year corresponding to the ISO week  number.   (For  example,
226              1991.)
227
228       %u     The day of the week as a decimal number (1–7, where Monday = 1).
229
230       %V     The  ISO  8601:1988  week number as a decimal number (1–53).  If
231              the week (starting on Monday) containing 1 January has  four  or
232              more days in the new year, then it is considered week 1.  Other‐
233              wise, it is the last week of the previous  year,  and  the  next
234              week is week 1.
235
236       %z     An RFC-822/ISO 8601 standard timezone specification.
237
238       %Z     The timezone name.
239
240       Similarly,  because of GNU extensions to strftime(3), %k is accepted as
241       a synonym for %H, and %l should be accepted as a synonym for %I, and %P
242       is accepted as a synonym for %p.  Finally
243
244       %s     The number of seconds since the Epoch, 1970-01-01 00:00:00 +0000
245              (UTC).  Leap seconds are not counted unless leap second  support
246              is available.
247
248       The  glibc implementation does not require whitespace between two field
249       descriptors.
250

EXAMPLES

252       The following example demonstrates the  use  of  strptime()  and  strf‐
253       time(3).
254
255       #define _XOPEN_SOURCE
256       #include <stdio.h>
257       #include <stdlib.h>
258       #include <string.h>
259       #include <time.h>
260
261       int
262       main(void)
263       {
264           struct tm tm;
265           char buf[255];
266
267           memset(&tm, 0, sizeof(tm));
268           strptime("2001-11-12 18:31:01", "%Y-%m-%d %H:%M:%S", &tm);
269           strftime(buf, sizeof(buf), "%d %b %Y %H:%M", &tm);
270           puts(buf);
271           exit(EXIT_SUCCESS);
272       }
273

SEE ALSO

275       time(2), getdate(3), scanf(3), setlocale(3), strftime(3)
276

COLOPHON

278       This  page  is  part of release 5.13 of the Linux man-pages project.  A
279       description of the project, information about reporting bugs,  and  the
280       latest     version     of     this    page,    can    be    found    at
281       https://www.kernel.org/doc/man-pages/.
282
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285GNU                               2021-03-22                       STRPTIME(3)
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