struct tm *getdate(const char *string);
extern int getdate_err;
#define _GNU_SOURCE
#include <time.h>
int getdate_r(const char *string, struct tm *res);
In contrast to strptime(3), (which has a format argument), getdate() uses the formats found in the file whose full pathname is given in the environment variable DATEMSK. The first line in the file that matches the given input string is used for the conversion.
The matching is done case insensitively. Superfluous whitespace, either in the pattern or in the string to be converted, is ignored.
The conversion specifications that a pattern can contain are those given for strptime(3). One more conversion specification is specified in POSIX.1-2001:
When %Z is given, the structure containing the broken-down time is initialized with values corresponding to the current time in the given timezone. Otherwise, the structure is initialized to the broken-down time corresponding to the current local time (as by a call to localtime(3)).
When only the weekday is given, the day is taken to be the first such day on or after today.
When only the month is given (and no year), the month is taken to be the first such month equal to or after the current month. If no day is given, it is the first day of the month.
When no hour, minute and second are given, the current hour, minute and second are taken.
If no date is given, but we know the hour, then that hour is taken to be the first such hour equal to or after the current hour.
getdate_r() is a GNU extension that provides a reentrant version of getdate(). Rather than using a global variable to report errors and a static buffer to return the broken down time, it returns errors via the function result value, and returns the resulting broken-down time in the caller-allocated buffer pointed to by the argument res.
On success getdate_r() returns 0; on error it returns one of the error numbers shown below.
$ TFILE=$PWD/tfile $ echo aq%Aaq > $TFILE # Full weekday name $ echo aq%Taq >> $TFILE # ISO date (YYYY-MM-DD) $ echo aq%Faq >> $TFILE # Time (HH:MM:SS) $ date $ export DATEMSK=$TFILE $ ./a.out Tuesday aq2009-12-28aq aq12:22:33aq Sun Sep 7 06:03:36 CEST 2008 Call 1 ("Tuesday") succeeded: tm_sec = 36 tm_min = 3 tm_hour = 6 tm_mday = 9 tm_mon = 8 tm_year = 108 tm_wday = 2 tm_yday = 252 tm_isdst = 1 Call 2 ("2009-12-28") succeeded: tm_sec = 36 tm_min = 3 tm_hour = 6 tm_mday = 28 tm_mon = 11 tm_year = 109 tm_wday = 1 tm_yday = 361 tm_isdst = 0 Call 3 ("12:22:33") succeeded: tm_sec = 33 tm_min = 22 tm_hour = 12 tm_mday = 7 tm_mon = 8 tm_year = 108 tm_wday = 0 tm_yday = 250 tm_isdst = 1
#define _GNU_SOURCE 500 #include <time.h> #include <stdio.h> #include <stdlib.h> int main(int argc, char *argv[]) { struct tm *tmp; int j; for (j = 1; j < argc; j++) { tmp = getdate(argv[j]); if (tmp == NULL) { printf("Call %d failed; getdate_err = %d\n", j, getdate_err); continue; } printf("Call %d (\"%s\") succeeded:\n", j, argv[j]); printf(" tm_sec = %d\n", tmp->tm_sec); printf(" tm_min = %d\n", tmp->tm_min); printf(" tm_hour = %d\n", tmp->tm_hour); printf(" tm_mday = %d\n", tmp->tm_mday); printf(" tm_mon = %d\n", tmp->tm_mon); printf(" tm_year = %d\n", tmp->tm_year); printf(" tm_wday = %d\n", tmp->tm_wday); printf(" tm_yday = %d\n", tmp->tm_yday); printf(" tm_isdst = %d\n", tmp->tm_isdst); } exit(EXIT_SUCCESS); }