1GETDATE(3) Linux Programmer's Manual GETDATE(3)
2
6 getdate, getdate_r - convert a date-plus-time string to broken-down
7 time
8
10 #define _XOPEN_SOURCE 500
11 #include <time.h>
12 struct tm *getdate(const char *string);
14 extern int getdate_err;
16 #define _GNU_SOURCE
18 #include <time.h>
19 int getdate_r(const char *string, struct tm *res);
21
23 The function getdate() converts a string representation of a date and
24 time, contained in the buffer pointed to by string, into a broken-down
25 time. The broken-down time is stored in a tm structure, and a pointer
26 to this structure is returned as the function result. This tm struc‐
27 ture is allocated in static storage, and consequently it will be over‐
28 written by further calls to getdate().
29 In contrast to strptime(3), (which has a format argument), getdate()
31 uses the formats found in the file whose full pathname is given in the
32 environment variable DATEMSK. The first line in the file that matches
33 the given input string is used for the conversion.
34 The matching is done case insensitively. Superfluous whitespace,
36 either in the pattern or in the string to be converted, is ignored.
37 The conversion specifications that a pattern can contain are those
39 given for strptime(3). One more conversion specification is specified
40 in POSIX.1-2001:
41 %Z Timezone name. This is not implemented in glibc.
43 When %Z is given, the structure containing the broken-down time is ini‐
45 tialized with values corresponding to the current time in the given
46 timezone. Otherwise, the structure is initialized to the broken-down
47 time corresponding to the current local time (as by a call to local‐
48 time(3)).
49 When only the weekday is given, the day is taken to be the first such
51 day on or after today.
52 When only the month is given (and no year), the month is taken to be
54 the first such month equal to or after the current month. If no day is
55 given, it is the first day of the month.
56 When no hour, minute and second are given, the current hour, minute and
58 second are taken.
59 If no date is given, but we know the hour, then that hour is taken to
61 be the first such hour equal to or after the current hour.
62 getdate_r() is a GNU extension that provides a reentrant version of
64 getdate(). Rather than using a global variable to report errors and a
65 static buffer to return the broken down time, it returns errors via the
66 function result value, and returns the resulting broken-down time in
67 the caller-allocated buffer pointed to by the argument res.
68
70 When successful, getdate() returns a pointer to a struct tm. Other‐
71 wise, it returns NULL and sets the global variable getdate_err to one
72 of the error numbers shown below. Changes to errno are unspecified.
73 On success getdate_r() returns 0; on error it returns one of the error
75 numbers shown below.
76
78 The following errors are returned via getdate_err (for getdate()) or as
79 the function result (for getdate_r()):
80 1 The DATEMSK environment variable is not defined, or its value is an
82 empty string.
83 2 The template file specified by DATEMSK cannot be opened for read‐
85 ing.
86 3 Failed to get file status information.
88 4 The template file is not a regular file.
90 5 An error was encountered while reading the template file.
92 6 Memory allocation failed (not enough memory available).
94 7 There is no line in the file that matches the input.
96 8 Invalid input specification.
98
100 DATEMSK
101 File containing format patterns.
102 TZ, LC_TIME
104 Variables used by strptime(3).
105
107 POSIX.1-2001.
108
110 The POSIX.1-2001 specification for strptime(3) contains conversion
111 specifications using the %E or %O modifier, while such specifications
112 are not given for getdate(). In glibc, getdate() is implemented using
113 strptime(3), so that precisely the same conversions are supported by
114 both.
115
117 The program below calls getdate() for each of its command-line argu‐
118 ments, and for each call displays the values in the fields of the
119 returned tm structure. The following shell session demonstrates the
120 operation of the program:
121 $ TFILE=$PWD/tfile
123 $ echo '%A' > $TFILE # Full weekday name
124 $ echo '%T' >> $TFILE # ISO date (YYYY-MM-DD)
125 $ echo '%F' >> $TFILE # Time (HH:MM:SS)
126 $ date
127 $ export DATEMSK=$TFILE
128 $ ./a.out Tuesday '2009-12-28' '12:22:33'
129 Sun Sep 7 06:03:36 CEST 2008
130 Call 1 ("Tuesday") succeeded:
131 tm_sec = 36
132 tm_min = 3
133 tm_hour = 6
134 tm_mday = 9
135 tm_mon = 8
136 tm_year = 108
137 tm_wday = 2
138 tm_yday = 252
139 tm_isdst = 1
140 Call 2 ("2009-12-28") succeeded:
141 tm_sec = 36
142 tm_min = 3
143 tm_hour = 6
144 tm_mday = 28
145 tm_mon = 11
146 tm_year = 109
147 tm_wday = 1
148 tm_yday = 361
149 tm_isdst = 0
150 Call 3 ("12:22:33") succeeded:
151 tm_sec = 33
152 tm_min = 22
153 tm_hour = 12
154 tm_mday = 7
155 tm_mon = 8
156 tm_year = 108
157 tm_wday = 0
158 tm_yday = 250
159 tm_isdst = 1
160 Program source
162 #define _GNU_SOURCE 500
164 #include <time.h>
165 #include <stdio.h>
166 #include <stdlib.h>
167 int
169 main(int argc, char *argv[])
170 {
171 struct tm *tmp;
172 int j;
173 for (j = 1; j < argc; j++) {
175 tmp = getdate(argv[j]);
176 if (tmp == NULL) {
178 printf("Call %d failed; getdate_err = %d\n",
179 j, getdate_err);
180 continue;
181 }
182 printf("Call %d (\"%s\") succeeded:\n", j, argv[j]);
184 printf(" tm_sec = %d\n", tmp->tm_sec);
185 printf(" tm_min = %d\n", tmp->tm_min);
186 printf(" tm_hour = %d\n", tmp->tm_hour);
187 printf(" tm_mday = %d\n", tmp->tm_mday);
188 printf(" tm_mon = %d\n", tmp->tm_mon);
189 printf(" tm_year = %d\n", tmp->tm_year);
190 printf(" tm_wday = %d\n", tmp->tm_wday);
191 printf(" tm_yday = %d\n", tmp->tm_yday);
192 printf(" tm_isdst = %d\n", tmp->tm_isdst);
193 }
194 exit(EXIT_SUCCESS);
196 }
197
199 time(2), localtime(3), setlocale(3), strftime(3), strptime(3), fea‐
200 ture_test_macros(7)
201
203 This page is part of release 3.22 of the Linux man-pages project. A
204 description of the project, and information about reporting bugs, can
205 be found at http://www.kernel.org/doc/man-pages/.
206 2008-09-07 GETDATE(3)