Thanks for the reply, Mariano! I tried your advice but I ended up with some
"Could not coerce arguments" errors and crashing the VM several times :P.
However, I tried something like this:

IplImage>>free
SqueakCV apiReleaseImage: handle asByteArrayPointer.

SqueakCV>>apiReleaseImage: doublePointer
<apicall: void 'cvReleaseImage' (byte*) module: 'cxcore110.dll'>
 ^ self externalCallFailed


It appears to be working. I don't know if this is the right way to do it,
though. I don't know either if overriding #free is ok and it would not bring
problems later...


> >* 2)      To finalize objects the OpenCV library defines some functions such*>* as cvReleaseImage, cvReleaseMat, etc. As far as I can tell, these functions*>* receive a pointer-to-pointer as argument. How can I declare such a method in*>* Squeak? Having one object, how can I get the pointer to that object? Should*>* I use the #getHandle method?*>**
> In OpenDBX we have a functions like this for example:
>
>     long odbx_init(odbx_t**, char*, char*, char*)
>
> This is how I declare it:
>
> apiInitialize: handle backend: backend host: host port: port
>     <cdecl: long 'odbx_init' (ulong* char* char* char*) module: 'opendbx'>
>     ^self externalCallFailed
>
> Remember a pinter to a pointer is a long :)
>
> And then in the code I do something like this:
>
> handleArray := WordArray with: 0.
>     err := OpenDBX current
>                 apiInitialize: handleArray
>                 backend: self backend
>                 host: aConnection settings host
>                 port: aConnection settings port.
>
> Notice the WordArray.
>
> I have no idea of 1) and 3) sorry.
>
> I hope this helps. If this do help, perhaps we can put it in FFI wiki page.
>
> Cheers,
>
> Mariano
>
>
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