Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!helios!bcm!dimacs.rutgers.edu!seismo!uunet!olivea!tymix!cirrusl!sunstorm!dhesi
From: dhesi%cirrusl@oliveb.ATC.olivetti.com (Rahul Dhesi)
Newsgroups: comp.std.c
Subject: Re: Frustrated trying to be portable
Message-ID: <2960@cirrusl.UUCP>
Date: 21 Feb 91 19:09:58 GMT
References: <1991Feb17.203337.20569@uokmax.ecn.uoknor.edu> <15240@smoke.brl.mil> <4188@skye.ed.ac.uk> <1991Feb20.175318.28496@zoo.toronto.edu>
Sender: news@cirrusl.UUCP
Organization: Cirrus Logic Inc.
Lines: 18

In <1991Feb20.175318.28496@zoo.toronto.edu> henry@zoo.toronto.edu
(Henry Spencer) writes:

     It is not possible to implement memmove(), in particular, in
     portable C.

This is unfortunately true.  My portable solution, is to assume that
the caller of memmove() always knows the direction of the move.   The
caller should therefore call either move_down() or move_up(), making
the same sort of decision about direction of the move that memmove()
would make anyway.  And move_down() and move_up() *can* be portably
implemented.  Lazy ANSI-conformant implementors can still do:

     #define move_down   memmove
     #define move_up     memmove
--
Rahul Dhesi <dhesi%cirrusl@oliveb.ATC.olivetti.com>
UUCP:  oliveb!cirrusl!dhesi