On Wed, May 13, 2009 at 5:57 PM, Ricardo Moran <richi.moran at gmail.com>wrote:

> Sorry, I sent it with the wrong subject. Here I go again:
>
> On Wed, May 13, 2009 at 3:41 PM, Ricardo Moran <richi.moran at gmail.com>wrote:
>
>> 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...
>>
>
Sorry about that ;)  I didn't know about byte and asByteArrayPointer. It
would be nice someone tell us if this is a better idea or not and give us
the reasons.

Mariano



>
>> >* 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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