Message-ID: <39FECC28.D1D66D47@antlimited.com>
Date: Tue, 31 Oct 2000 13:42:00 +0000
From: Richard Heathfield <richard AT antlimited DOT com>
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CC: rwallace AT esatclear DOT ie
Subject: Re: Undertaking a programming journey
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[Russell's answer prompted me to re-read the thing he was answering, and
I spotted a bug...
 Courtesy copy emailed to Russell]

Richard Heathfield wrote:

<snip>

> For example, there's one OS that interprets even return codes
> as failures, and odd return codes as successes! (Is it VMS?)
> 
> Now, if you return 0 or EXIT_SUCCESS from your program, either via a
> return from main() or from exit(), a conforming C compiler guarantees
> that it will translate that value into the value interpreted by the OS
> as "success". If you return EXIT_FAILURE, the compiler guarantees that
                              ^^^^^^^^^^^^

should be EXIT_SUCCESS (!)

> it will translate /that/ value into the value interpreted by the OS as
> "failure". Thus, in the case of VMS(?), the compiler will translate
   ^^^^^^^

should be "success"

> "return 0;" into "return some odd number or other" for you, and "return
> EXIT_FAILURE;" into "return some odd number or other" (and,
  ^^^^^^^^^^^^

should be EXIT_SUCCESS

The point I was trying to make here, and failing, is that EXIT_SUCCESS
and 0 would both be translated into odd numbers for this particular OS,
but that those numbers need not be the same as each other.

> interestingly, it need not be the /same/ odd number as for "return 0"!
> (although it probably will be, I guess)). Similarly, a VMS(?) C compiler
> would ensure that "return EXIT_FAILURE" returned an even number to the
> OS.
> 
> No other values than the ones cited are semantically portable.
> 
> I hope that clarifies matters for the OP.

And I hope this clarifies matters even more. (sigh)


-- 
Richard Heathfield
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
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