🚀 go-pugleaf

In article <43q1ko$q5s@Radon.Stanford.EDU>, becker@Xenon.Stanford.EDU
(Denizen of the Deep) writes: 
<snip>
|> So if I write a program which invokes undefined behavior all over
|> the place, but I can find one conforming implementation which will
|> accept it, then I can say that my program is a conforming C
|> program?

Yes. That is why a conforming C program is a practically meaningless term.

|> 
|> This gives new meaning to the whole "void main(void)" debate.  After
|> all, I know plenty of implementations which will accept that (and
|> some of them are even conforming :-).

Theorem: As long as there exists a conforming C implementation on a powerful
enough OS, no program is ever a non-conforming C program.

Proof: Let us say that we are testing X for conformance.
       Create a file called X which contains the above program.
       Write the following shell script (or its equivalent in that OS)
        #!/bin/sh
        if ! $(COMPILE) X ; then
          if ! diff X $1 ; then
            cp `which true` a.out
          fi
        fi
       This shell script (along with proper documentation and run time
       support) is trivially a conforming implementation with the proper
       definition of COMPILE: and it `compiles' X to a program that runs
       without error. 

|> 
|> What exactly does it mean to say that an implementation "accepts"
|> a program?  That it successfully compiles it (with or without
|> non-fatal warnings)?

None of these is precisely defined in the standard. However, as I said: it
does not matter. I could trivially modify the above to make any given X
compile without diagnostic!

Cheers
Tanmoy
-- 
tanmoy@qcd.lanl.gov(128.165.23.46) DECNET: BETA::"tanmoy@lanl.gov"(1.218=1242)
Tanmoy Bhattacharya O:T-8(MS B285)LANL,NM87544-0285,USA H:#3,802,9 St,NM87545
Others see <gopher://yaleinfo.yale.edu:7700/00/Internet-People/internet-mail>,
<http://alpha.acast.nova.edu/cgi-bin/inmgq.pl>or<ftp://csd4.csd.uwm.edu/pub/
internetwork-mail-guide>. -- <http://nqcd.lanl.gov/people/tanmoy/tanmoy.html>
fax: 1 (505) 665 3003   voice: 1 (505) 665 4733    [ Home: 1 (505) 662 5596 ]