Re: Proposal for sc_process_handle: AGREE

John, Bishnupriya,

a straight-forward implementation (e.g. based on unique ids with a
"magic id" 0 for empty handles) would lead to equivalent empty handles.
See below.

On 24/03/10 12:37, john.aynsley@doulos.com wrote:
> Bishnupriya,
>
> You wrote
>
> I agree that using an unique integer id for each process object will allow
> an invalidating implementation to implement operator < correctly, as laid
> down below in Philip's 3 bullet points. Note that the corner case of two
> invalid handles where the handles never did point to any process objects
> need also be covered, and such handles should not be equivalent, and
> should not be equal (i.e. they should be unequal)
> sc_process_handle a,b;
> sc_assert(!(a<b) && !(b<a));
> sc_assert(a!=b);

This original code is what I would have expected: empty handles are
unequal (as per current standard), but equivalent (neither is "less
than" the other).

> I think you meant:
>
> sc_process_handle a,b;
> sc_assert( (a<b) || (b<a) );

In this case, you could fill up a map with empty handles indefinitely
(and never find empty handles in such a container):

std::map< sc_process_handle, int > m;
sc_process_handle no_proc;

for( int i=0; i<10; ++i )
   // always adds a new entry to the map :(
   m[ no_proc ]++;

So I think, the original code example of Bishnupriya has been correct,
and the explaining text contained a typo. Am I right?

Greetings from Oldenburg,
Philipp

[snip]

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Philipp A. Hartmann
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