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From: pshuang@athena.mit.edu (Ping-Shun Huang)
Subject: Re: finding the day of week from the date
In-Reply-To: gideon@cs.utexas.edu's message of 22 Jun 91 16:17:56 GMT
Message-ID: <PSHUANG.91Jun23160834@beeblebrox.mit.edu>
Sender: news@athena.mit.edu (News system)
Organization: Massachusetts Institute of Technology
References: <tr.677526990@samadams> <1468@ai.cs.utexas.edu>
Date: Sun, 23 Jun 91 20:08:42 GMT
Lines: 19

In article <1468@ai.cs.utexas.edu> gideon@cs.utexas.edu (Timothy Tin-Wai Chan) writes:

 >      So apparently DOS finds the day of the week itself.  The question is,
 > how can I use this facility in DOS?

Have your program query DOS for the current date.  Save it.  Set the DOS
date to the date you want to know about.  Read the day-of-week (see
HELPPC or the commonly available interrupt list -- it's probably in the
BIOS data area if DOS does not provide an service which explicitly
returns it).  Set the DOS date back to the current date.  End.

Disadvantages: there are sharp limits to how early you can set the DOS
date (1-1-80 may well be the earliest date you can set it to, not
positive).  You're also taking a chance that Microsoft's code to
determine the day of week may be buggy.

--
Above text where applicable is (c) Copyleft 1991, all rights deserved by:
UNIX:/etc/ping instantiated (Ping Huang) [INTERNET: pshuang@athena.mit.edu]
