getdate(3C) DG/UX 5.4R3.00 getdate(3C)
NAME
getdate, getdateerr - convert user format date and time
SYNOPSIS
#include <time.h>
struct tm *getdate (const char *string);
extern int getdateerr;
DESCRIPTION
getdate converts user-definable date and/or time specifications
pointed to by string into a tm structure. The structure declaration
is in the time.h header file [see also ctime(3C)].
User-supplied templates are used to parse and interpret the input
string. The templates are text files created by the user and
identified via the environment variable DATEMSK. Each line in the
template represents an acceptable date and/or time specification
using some of the same field descriptors as the ones used by the date
command. The first line in the template that matches the input
specification is used for interpretation and conversion into the
internal time format. If successful, the function getdate returns a
pointer to a tm structure; otherwise, it returns NULL and sets the
global variable getdateerr to indicate the error.
The following field descriptors are supported:
%% same as %
%a abbreviated weekday name
%A full weekday name
%b abbreviated month name
%B full month name
%c locale's appropriate date and time representation
%d day of month (01-31; the leading 0 is optional)
%e same as %d
%D date as %m/%d/%y
%h abbreviated month name
%H hour (00-23)
%I hour (01-12)
%m month number (01-12)
%M minute (00-59)
%n same as \n
%p locale's equivalent of either AM or PM
%r time as %I:%M:%S %p
%R time as %H:%M
%S seconds (00-59)
%t insert a tab
%T time as %H:%M:%S
%w weekday number (0-6; Sunday = 0)
%x locale's appropriate date representation
%X locale's appropriate time representation
%y year with century (00-99)
%Y year as ccyy (e.g., 1986)
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%Z time zone name or no characters if no time zone exists
The month and weekday names can consist of any combination of upper
and lower case letters. The user can request that the input date or
time specification be in a specific language by setting the
categories LCTIME and LCCTYPE of setlocale.
The following example shows the possible contents of a template:
%m
%A %B %d %Y, %H:%M:%S
%A
%B
%m/%d/%y %I %p
%d,%m,%Y %H:%M
at %A the %dst of %B in %Y
run job at %I %p,%B %dnd
%A den %d. %B %Y %H.%M Uhr
The following are examples of valid input specifications for the
above template:
getdate("10/1/87 4 PM")
getdate("Friday")
getdate("Friday September 19 1987, 10:30:30")
getdate("24,9,1986 10:30")
getdate("at monday the 1st of december in 1986")
getdate("run job at 3 PM, december %2nd")
If the LANG environment variable is set to german, the following is
valid:
getdate("freitag den 10. oktober 1986 10.30 Uhr")
Local time and date specification are also supported. The following
examples show how local date and time specification can be defined in
the template.
+---------------------------+------------------+
| Invocation | Line in Template |
+---------------------------+------------------+
|getdate("11/27/86") | %m/%d/%y |
|getdate("27.11.86") | %d.%m.%y |
|getdate("86-11-27") | %y-%m-%d |
|getdate("Friday 12:00:00") | %A %H:%M:%S |
+---------------------------+------------------+
The following rules are applied for converting the input
specification into the internal format:
If only the weekday is given, today is assumed if the given
day is equal to the current day and next week if it is less.
If only the month is given, the current month is assumed if
the given month is equal to the current month and next year if
it is less and no year is given. (The first day of month is
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assumed if no day is given.)
If no hour, minute, and second are given, the current hour,
minute, and second are assumed.
If no date is given, today is assumed if the given hour is
greater than the current hour and tomorrow is assumed if it is
less.
The following examples illustrate the above rules. Assume that the
current date is Mon Sep 22 12:19:47 EDT 1986 and the LANG environment
variable is not set.
+-------------+------------------+------------------------------+
| Input | Line in Template | Date |
+-------------+------------------+------------------------------+
|Mon | %a | Mon Sep 22 12:19:48 EDT 1986 |
|Sun | %a | Sun Sep 28 12:19:49 EDT 1986 |
|Fri | %a | Fri Sep 26 12:19:49 EDT 1986 |
|September | %B | Mon Sep 1 12:19:49 EDT 1986 |
|January | %B | Thu Jan 1 12:19:49 EST 1987 |
|December | %B | Mon Dec 1 12:19:49 EST 1986 |
|Sep Mon | %b %a | Mon Sep 1 12:19:50 EDT 1986 |
|Jan Fri | %b %a | Fri Jan 2 12:19:50 EST 1987 |
|Dec Mon | %b %a | Mon Dec 1 12:19:50 EST 1986 |
|Jan Wed 1989 | %b %a %Y | Wed Jan 4 12:19:51 EST 1989 |
|Fri 9 | %a %H | Fri Sep 26 09:00:00 EDT 1986 |
|Feb 10:30 | %b %H:%S | Sun Feb 1 10:00:30 EST 1987 |
|10:30 | %H:%M | Tue Sep 23 10:30:00 EDT 1986 |
|13:30 | %H:%M | Mon Sep 22 13:30:00 EDT 1986 |
+-------------+------------------+------------------------------+
Considerations for Threads Programming
+---------+-----------------------------+
| | async- |
|function | reentrant cancel cancel |
| | point safe |
+---------+-----------------------------+
|getdate | N - - |
+---------+-----------------------------+
getdate calls should be made when other threads in a process are not
changing the LANG environment variable, LCCTYPE nor LCTIME.
See the setlocale(3C) and putenv(3C) man pages for more information.
FILES
/usr/lib/locale/locale/LCTIME language specific printable files
/usr/lib/locale/locale/LCCTYPE code set specific printable files
DIAGNOSTICS
On failure getdate returns NULL and sets the variable getdateerr to
indicate the error.
The following is a complete list of the getdateerr settings and
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their meanings.
1 The DATEMSK environment variable is null or undefined.
2 The template file cannot be opened for reading.
3 Failed to get file status information.
4 The template file is not a regular file.
5 An error is encountered while reading the template file.
6 malloc failed (not enough memory is available).
7 There is no line in the template that matches the input.
8 The input specification is invalid (e.g., February 31).
SEE ALSO
reentrant(3), setlocale(3C), ctype(3C), environ(5).
NOTES
Subsequent calls to getdate alter the contents of getdateerr.
Dates before 1970 and after 2037 are illegal.
getdate makes explicit use of macros described in ctype(3C).
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