Re: Storing C++ data in an instance field using CNI?

[David Daney <ddaney at avtrex dot com>]

Paul Gear wrote:

> Hi folks,
>
> I've searched the archives & Google without finding an answer to this
> question: is it possible using CNI to store C++ data in the object as an
> instance field?
>
> I need to store a struct defined in an external library within the
> object.  Can i just define a field that is of type Object and then use
> that as a pointer?  If i do this, do i need to use special malloc/free
> routines?
>
> Thanks in advance,
> Paul
> http://paulgear.webhop.net
>  
I think the traditional way to do it with JNI and CNI is to define an 
int (or long if using 64 bit pointers) member in the java object that 
will be casted to a pointer to the C++ data object.  The C++ data object 
would be allocated with operator new or malloc.  You have to arrange to 
delete/free it before the java object is GCed.  This can be done from 
the finalize method.

David Daney.