Path: utzoo!mnetor!uunet!husc6!bbn!uwmcsd1!ig!agate!ucbvax!cbosgd!osu-cis!tut!lvc
From: lvc@tut.cis.ohio-state.edu (Lawrence V. Cipriani)
Newsgroups: comp.lang.c
Subject: Re: Some possible deficiencies in dpANS (or whatever its called)
Message-ID: <5009@tut.cis.ohio-state.edu>
Date: 21 Jan 88 14:51:09 GMT
References: <4755@tut.cis.ohio-state.edu> <7134@brl-smoke.ARPA>
Organization: Ohio State Computer & Info Science
Lines: 47
Keywords: none
Summary: I take it all back!

In article <7134@brl-smoke.ARPA>, gwyn@brl-smoke.ARPA (Doug Gwyn ) writes:
> In article <4755@tut.cis.ohio-state.edu> lvc@tut.cis.ohio-state.edu (Lawrence V. Cipriani) writes:
> >it looks like the following are valid *statements*:
> >	i;
> >	j << 2;
> >	k == 0;
> >	"hello world\n";
> 
> Yes.
> 
> >I believe this is a deficiency.  These statements have no effect ...
> 
> Such statements may be produced by macro expansion.  There doesn't
> seem to be any reason to outlaw them.  In fact, the first three
> all "touch" a variable and therefore do have a practical effect,
> sometimes.

Think Larry think!  I take it back, they should not be prohibited.

Also, I did not mean to include functions as having null effect.
Even functions that do have null effect can be useful.

> 
> >and in fact lint flags them.
> 
> This is probably the best way to protect against actual errors
> like this.

Yes, however, the first three errors were in code that was literally
impossible to lint since there were no lint librares; it was in SVR2
(well at least the version we hack up on my project).  Also, some users
of C do not have lint.  It would be desirable if these at least produced
warnings.  This is what I will suggest to X3J11.

> >2)  In the definition of the sizeof operator, the sentence
	...

Thanks for the info on sizeof for arrays.  Be warned that I am
collecting all context diffs and postings of the proposed standard
and in about 10 years I should have it free of any copyright
restrictions!

-- 
oo
Larry Cipriani, AT&T Networks Systems (by day) Ohio State University (by night)
Domain: lvc@tut.cis.ohio-state.edu
Path: ...!cbosgd!osu-cis!tut.cis.ohio-state.edu!lvc (yes its right)