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From: rbutterworth@orchid.UUCP
Newsgroups: comp.lang.c
Subject: Re: NULL pointers as arguments, really condition expressions
Message-ID: <7327@orchid.UUCP>
Date: Tue, 5-May-87 10:46:38 EDT
Article-I.D.: orchid.7327
Posted: Tue May  5 10:46:38 1987
Date-Received: Wed, 6-May-87 05:45:51 EDT
References: <1130@ius2.cs.cmu.edu> <148@nbisos.NBI.COM> <801@rtech.UUCP>
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Organization: U of Waterloo, Ontario
Lines: 22

In article <801@rtech.UUCP>, daveb@rtech.UUCP (Dave Brower) writes:
> Which reminds me of a general problem with the conditional operator.
> What is the type of the result of evaluating:
>     (expr) ? (double) x : (char)y
>     * Take the type of the true expression as the type of the whole.
>     * Take the type of the false expression...
>     * Take the type of the lval, if any.
>     * Take the type of the "biggest" type of the true or false expr.
>     * Call it an error.

I'd call it an error.  But how about
    intptr = (expr) ? void_star_func() : float_star_func() ;

I haven't checked the latest draft, but an earlier ANSI draft
indicated that the type of ?(void*):(type*) would be (void*).

This is definitely not the way it should be, as the above
example would compile and lint cleanly even though it is
wrong.  I hope ANSI has or will change it to indicate that
the result of a ":" with a (void*) is the type of the other
pointer (and that other mixed used of ":" would be treated
according to the usual widening and promotion rules).