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Re: Help with bit-field semantics in C and C++
Joe Buck <Joe.Buck@synopsys.COM> writes:
| [ here E is a four-valued enum, 0,1,2,3 ]
|
| On Tue, Aug 24, 2004 at 04:09:02PM -0700, Mike Stump wrote:
| > (E)n, where n is an int with value, say of 7, is permitted by the
| > standard to take on the value 7. This is because the text of the
| > standard says the value is unspecified. 7 is a unspecified value,
| > honest.
|
| I agree with you so far; (E)n might be 7.
I disagree that the enum object would have value 7, as 7 is not an
enumeration (E) value.
| The next question, then, is whether, despite this, a compiler is allowed
| to implement a switch on a variable of type E as a jump table, in such a
| way that a value outside of [0,3] malfunctions (jumps to a random address).
By the type properties confered to E, any value of that type is in the
range [0,3].
| Let's leave to one side whether this is a good idea. Is it permitted?
That can't happen.
-- Gaby