Comma operator in constant expression

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Article #4234

#4234

From: Paul Long
Date: Mon, 16 Oct 1995 20:23

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1538 bytes

Is an implementation required to generate a diagnostic for this declaration?

   static int i = 1 ? 3 : (1, 2);

A constraint in section 6.4 says "Constant expressions shall not contain ...
comma operators..." However, a 6.4 Semantics passage says "An implementation
may accept other forms of constant expressions."

This rather large Semantics loophole does not remove the requirement to
generate a diagnostic for the constraint violation though, right? IOW, an
implementation may "accept" a comma operator in a constant expression, but it
must also generate a diagnostic. Neither Sun's acc compiler or Gnu's 2.6.0
compiler generate a diagnostic for this declaration. Does that mean that they
are NOT conforming implementations? If they are, please explain.

-- 
Paul Long                               45:29:14N 122:48:09W
plong@perf.com                          http://www.teleport.com/~pciwww/
    "Where time or intelligence are lacking, a goto may do the job."
        - M.E. Hopkins, "A Case for the GOTO," 1972.

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From: Paul Long <plong@perf.com>
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Subject: Comma operator in constant expression
Date: 16 Oct 1995 20:23:11 GMT
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