Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ames!nrl-cmf!mailrus!uflorida!novavax!proxftl!bill
From: bill@proxftl.UUCP (T. William Wells)
Newsgroups: comp.lang.c
Subject: Re: Overlapping assignments
Message-ID: <724@proxftl.UUCP>
Date: 8 Sep 88 00:48:49 GMT
References: <3008@tekcrl.CRL.TEK.COM>
Reply-To: bill@proxftl.UUCP (T. William Wells)
Organization: Proximity Technology, Ft. Lauderdale
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In article <3008@tekcrl.CRL.TEK.COM> barts@tekcrl.CRL.TEK.COM (Bart Schaefer) writes:
: Suppose I make the following declaration:
:
: [declaration omitted]
:
: Given that declaration, is the following assignment guaranteed to work
: for any (integer) values of i and j (assuming a compiler that supports
: structure assignment)?
:
: some_node.n_cell[i] = some_node.n_vec.args[j];

No.  If there is any possibility of overlap, you can be that some
compiler will move them in such a way as to make you miserable.

The new standard specifically states that the implementation does
not have to do such assignments correctly.  See 3.3.16.1.

---
Bill
novavax!proxftl!bill