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Diffstat (limited to 'man/man3/getdate.3')
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diff --git a/man/man3/getdate.3 b/man/man3/getdate.3 new file mode 100644 index 0000000..f710356 --- /dev/null +++ b/man/man3/getdate.3 @@ -0,0 +1,322 @@ +'\" t +.\" Copyright 2001 walter harms (walter.harms@informatik.uni-oldenburg.de) +.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk +.\" <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" Modified, 2001-12-26, aeb +.\" 2008-09-07, mtk, Various rewrites; added an example program. +.\" +.TH getdate 3 2024-05-02 "Linux man-pages (unreleased)" +.SH NAME +getdate, getdate_r \- convert a date-plus-time string to broken-down time +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B "#include <time.h>" +.P +.BI "struct tm *getdate(const char *" string ); +.P +.B "extern int getdate_err;" +.P +.BI "int getdate_r(const char *restrict " string ", struct tm *restrict " res ); +.fi +.P +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.P +.BR getdate (): +.nf + _XOPEN_SOURCE >= 500 +.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED +.fi +.P +.BR getdate_r (): +.nf + _GNU_SOURCE +.fi +.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 (). +.P +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. +.P +The matching is done case insensitively. +Superfluous whitespace, either in the pattern or in the string to +be converted, is ignored. +.P +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. +.P +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)). +.P +When only the day of the week is given, +the day is taken to be the first such day +on or after today. +.P +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. +.P +When no hour, minute, and second are given, the current +hour, minute, and second are taken. +.P +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. +.P +.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 +.I getdate_err +to one of the error numbers shown below. +Changes to +.I errno +are unspecified. +.P +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 +.I 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 +.B TZ +.TQ +.B 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 lbx +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR getdate () +T} Thread safety T{ +.na +.nh +MT-Unsafe race:getdate env locale +T} +T{ +.na +.nh +.BR getdate_r () +T} Thread safety T{ +.na +.nh +MT-Safe env locale +T} +.TE +.SH VERSIONS +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 STANDARDS +POSIX.1-2008. +.SH HISTORY +POSIX.1-2001. +.SH EXAMPLES +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: +.P +.in +4n +.EX +.RB "$" " TFILE=$PWD/tfile" +.RB "$" " echo \[aq]%A\[aq] > $TFILE " " # Full name of the day of the week" +.RB "$" " echo \[aq]%T\[aq] >> $TFILE" " # Time (HH:MM:SS)" +.RB "$" " echo \[aq]%F\[aq] >> $TFILE" " # ISO date (YYYY\-MM\-DD)" +.RB "$" " date" +.RB "$" " export DATEMSK=$TFILE" +.RB "$" " ./a.out Tuesday \[aq]2009\-12\-28\[aq] \[aq]12:22:33\[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 +.EE +.in +.SS Program source +\& +.\" SRC BEGIN (getdate.c) +.EX +#define _GNU_SOURCE +#include <stdio.h> +#include <stdlib.h> +#include <time.h> +\& +int +main(int argc, char *argv[]) +{ + struct tm *tmp; +\& + for (size_t j = 1; j < argc; j++) { + tmp = getdate(argv[j]); +\& + if (tmp == NULL) { + printf("Call %zu failed; getdate_err = %d\en", + j, getdate_err); + continue; + } +\& + printf("Call %zu (\e"%s\e") succeeded:\en", j, argv[j]); + printf(" tm_sec = %d\en", tmp\->tm_sec); + printf(" tm_min = %d\en", tmp\->tm_min); + printf(" tm_hour = %d\en", tmp\->tm_hour); + printf(" tm_mday = %d\en", tmp\->tm_mday); + printf(" tm_mon = %d\en", tmp\->tm_mon); + printf(" tm_year = %d\en", tmp\->tm_year); + printf(" tm_wday = %d\en", tmp\->tm_wday); + printf(" tm_yday = %d\en", tmp\->tm_yday); + printf(" tm_isdst = %d\en", tmp\->tm_isdst); + } +\& + exit(EXIT_SUCCESS); +} +.EE +.\" SRC END +.SH SEE ALSO +.BR time (2), +.BR localtime (3), +.BR setlocale (3), +.BR strftime (3), +.BR strptime (3) |