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From: jsdy@hadron.UUCP (Joseph S. D. Yao)
Newsgroups: net.lang.c,net.bugs
Subject: Re: C Compiler bug (and fix for a different one)
Message-ID: <504@hadron.UUCP>
Date: Thu, 31-Jul-86 01:35:20 EDT
Article-I.D.: hadron.504
Posted: Thu Jul 31 01:35:20 1986
Date-Received: Thu, 31-Jul-86 23:47:17 EDT
References: <273@watmath.UUCP> <5858@alice.uUCp> <461@watmath.UUCP>
Reply-To: jsdy@hadron.UUCP (Joseph S. D. Yao)
Organization: Hadron, Inc., Fairfax, VA
Lines: 28
Summary: (A) Different version mof X3J11?  (B) Counter-intuitive.
Xref: mnetor net.lang.c:5509 net.bugs:300

In article <461@watmath.UUCP> rbutterworth@watmath.UUCP (Ray Butterworth) writes:
>> > void f3(which)
>> > {
>> >     extern void f1(),f2();
>> >     which?f1():f2();
>> > }
>> > cc(1) gives an "incompatible types" error.
>> As it should.  The only thing you're allowed to do with void values
>> is throw them away.
>If I'm not throwing them away, what is it you think I'm doing with them?
>Also, the proposed ANSI draft explicitly states that the second and third
>operands of ?: may each have (void) type, so I'm not trying anything
>unusual here.

My 1984 version of X3J11 (has it been that long?) agrees with K&R
that each of the operands must have a value.  This makes intuitive
sense.  The meaning of X ? Y : Z is: an expression whose value is
the value of Y, if the value of X is non-zero; otherwise, the value
of Z.  By this, all three must evaluate to some value.

Do you have a more recent edition of X3J11 that  r e a l l y  lets
voids in there?  Ugh!  (What date?)  Besides which, all C compilers
until just recently (Lattice, Microsoft) had been written to K&R
and v7-s3-s5, not to the ANSI standard.
-- 

	Joe Yao		hadron!jsdy@seismo.{CSS.GOV,ARPA,UUCP}
			jsdy@hadron.COM (not yet domainised)