Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!rochester!pt.cs.cmu.edu!b.gp.cs.cmu.edu!Ralf.Brown@B.GP.CS.CMU.EDU
From: Ralf.Brown@B.GP.CS.CMU.EDU
Newsgroups: comp.sys.ibm.pc
Subject: Re: DOS 4.0 Compatibility Issues (LONG)
Summary: even documented functions have changed
Message-ID: <231d4c3d@ralf>
Date: 1 Sep 88 14:10:21 GMT
Sender: netnews@pt.cs.cmu.edu
Lines: 18
In-Reply-To: <2644@ukecc.engr.uky.edu>

In article <2644@ukecc.engr.uky.edu>, kenny@engr.uky.edu (Kenny Pitt) writes:
}.... I quote here directly from page 281
}of my copy of "The Peter Norton Programmer's Guide to the IBM PC."
}
}    Any DOS function that is not
}    publicly advertised as an available service cannot be relied upon
}    to be usable in future revisions of DOS.

Just because a function is documented does not mean it will stay the same in
future releases, either.  INT 21h/AH=38h (Get Country-Dependent Information)
changed rather drastically between DOS 2.x and 3.x, and not entirely in an
upwardly-compatible fashion (the buffer for returned data has everything past
the second item shifted by four bytes).
--
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