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From: bill@twwells.com (T. William Wells)
Newsgroups: comp.std.c
Subject: Re: Common malloc/free practice violates ANSI standard ?
Message-ID: <1989Oct30.104153.804@twwells.com>
Date: 30 Oct 89 10:41:53 GMT
References: <1989Oct14.043811.669@anucsd.oz> <1989Oct19.101306.16791@twwells.com> <1328@crdos1.crd.ge.COM>
Organization: None, Ft. Lauderdale, FL
Lines: 24

In article <1328@crdos1.crd.ge.COM> davidsen@crdos1.UUCP (bill davidsen) writes:
: In article <1989Oct19.101306.16791@twwells.com>, bill@twwells.com (T. William Wells) writes:
: |  The standard requires that casting from (void*) to (OBJ*) and back
: |  give pointers that compare equal and point to the same object.
: |  Free will have no problems with it.
:
:   I think you said this backward (or you misread it). You can cast *to*
: a void pointer and *back* without loss of information, but not the
: other way 'round. On machines which require allignment at all,
: assignment to a pointer to an alligned type may result in loss of
: information via rounding.

My error. I should have said, somewhere, that all this is
dependent on knowing that the pointer really can point to an OBJ,
as in the result of a malloc.

I hope that my later articles have adequately corrected this
mistake.

Sorry I wasn't more careful.

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Bill                    { uunet | novavax | ankh | sunvice } !twwells!bill
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