Patch: Document and prototype JvAllocBytes() for CNI

[Bryce McKinlay]

Tom Tromey wrote:

>>>>>>"Bryce" == Bryce McKinlay <mckinlay@redhat.com> writes:
>>>>>>            
>>>>>>
>
>Bryce> +This function can be useful if you need to associate some native data with a
>Bryce> +Java object (perhaps stored in a RawData field - @pxref{Mixing with C++,,The
>Bryce> +RawData Type}), 
>
>Actually you don't want to store _Jv_AllocBytes results in a RawData
>field.  It will just be collected instantly as these fields are not
>scanned.
>  
>

Hmm, good point. I keep forgetting about that.

>I wonder whether we should support _Jv_AllocBytes as a user API at
>all.  I suppose it is useful for local allocations.  But do we really
>want to support storing the result of _Jv_AllocBytes in a field with
>type Object?  I'm concerned that we may want, at some future date, to
>be able to assume that field types are actually meaningful.
>  
>

I think we need a varient of the RawData type that is scanned. There are 
places in libgcj where we use "Object" to store native data.

Regards

Bryce