.\" Copyright 2001 walter harms (walter.harms@informatik.uni-oldenburg.de) .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk .\" .\" .\" %%%LICENSE_START(VERBATIM) .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one. .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" %%%LICENSE_END .\" .\" Modified, 2001-12-26, aeb .\" 2008-09-07, mtk, Various rewrites; added an example program. .\" .TH GETDATE 3 2016-03-15 "" "Linux Programmer's Manual" .SH NAME getdate, getdate_r \- convert a date-plus-time string to broken-down time .SH SYNOPSIS .B "#include " .sp .BI "struct tm *getdate(const char *" string ); .sp .B "extern int getdate_err;" .sp .B "#include " .sp .BI "int getdate_r(const char *" string ", struct tm *" res ); .sp .in -4n Feature Test Macro Requirements for glibc (see .BR feature_test_macros (7)): .in .sp .BR getdate (): .ad l .RS 4 _XOPEN_SOURCE\ >=\ 500 .\" || _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED .RE .br .BR getdate_r (): .ad l .RS 4 _GNU_SOURCE .RE .ad .SH DESCRIPTION The function .BR getdate () converts a string representation of a date and time, contained in the buffer pointed to by .IR string , into a broken-down time. The broken-down time is stored in a .I tm structure, and a pointer to this structure is returned as the function result. This .I tm structure is allocated in static storage, and consequently it will be overwritten by further calls to .BR getdate (). In contrast to .BR strptime (3), (which has a .I format argument), .BR getdate () uses the formats found in the file whose full pathname is given in the environment variable .BR 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 .BR strptime (3). One more conversion specification is specified in POSIX.1-2001: .TP .B %Z Timezone name. .\" FIXME Is it (still) true that %Z is not supported in glibc? .\" Looking at the glibc 2.21 source code, where the implementation uses .\" strptime(), suggests that it might be supported. This is not implemented in glibc. .LP When .B %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 .BR localtime (3)). .LP When only the day of the week is given, the day is taken to be the first such day on or after today. .LP 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. .LP When no hour, minute and second are given, the current hour, minute and second are taken. .LP 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. .BR getdate_r () is a GNU extension that provides a reentrant version of .BR 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 .IR res . .SH RETURN VALUE When successful, .BR getdate () returns a pointer to a .IR "struct tm" . Otherwise, it returns NULL and sets the global variable .IR getdate_err to one of the error numbers shown below. Changes to .I errno are unspecified. On success .BR getdate_r () returns 0; on error it returns one of the error numbers shown below. .SH ERRORS The following errors are returned via .IR getdate_err (for .BR getdate ()) or as the function result (for .BR getdate_r ()): .TP 4n .B 1 The .B DATEMSK environment variable is not defined, or its value is an empty string. .TP .B 2 The template file specified by .B DATEMSK cannot be opened for reading. .TP .B 3 Failed to get file status information. .\" stat() .TP .B 4 The template file is not a regular file. .TP .B 5 An error was encountered while reading the template file. .TP .B 6 Memory allocation failed (not enough memory available). .\" Error 6 doesn't seem to occur in glibc .TP .B 7 There is no line in the file that matches the input. .TP .B 8 Invalid input specification. .SH ENVIRONMENT .TP .B DATEMSK File containing format patterns. .TP .BR TZ ", " LC_TIME Variables used by .BR strptime (3). .SH ATTRIBUTES For an explanation of the terms used in this section, see .BR attributes (7). .TS allbox; lb lb lb l l l. Interface Attribute Value T{ .BR getdate () T} Thread safety MT-Unsafe race:getdate env locale T{ .BR getdate_r () T} Thread safety MT-Safe env locale .TE .SH CONFORMING TO POSIX.1-2001, POSIX.1-2008. .SH NOTES The POSIX.1 specification for .BR strptime (3) contains conversion specifications using the .B %E or .B %O modifier, while such specifications are not given for .BR getdate (). In glibc, .BR getdate () is implemented using .BR strptime (3), so that precisely the same conversions are supported by both. .SH EXAMPLE The program below calls .BR getdate () for each of its command-line arguments, and for each call displays the values in the fields of the returned .I tm structure. The following shell session demonstrates the operation of the program: .in +4n .nf .RB "$" " TFILE=$PWD/tfile" .RB "$" " echo \(aq%A\(aq > $TFILE " " # Full name of the day of the week" .RB "$" " echo \(aq%T\(aq >> $TFILE" " # ISO date (YYYY-MM-DD)" .RB "$" " echo \(aq%F\(aq >> $TFILE" " # Time (HH:MM:SS)" .RB "$" " date" .RB "$" " export DATEMSK=$TFILE" .RB "$" " ./a.out Tuesday \(aq2009-12-28\(aq \(aq12:22:33\(aq" 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 .fi .in .SS Program source \& .nf #define _GNU_SOURCE #include #include #include 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); } .fi .SH SEE ALSO .BR time (2), .BR localtime (3), .BR setlocale (3), .BR strftime (3), .BR strptime (3) .SH COLOPHON This page is part of release 4.10 of the Linux .I man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at \%https://www.kernel.org/doc/man\-pages/.