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On Wed, May 13, 2009 at 5:57 PM, Ricardo Moran <[hidden email]> wrote:
Sorry, I sent it with the wrong subject. Here I go again:
On Wed, May 13, 2009 at 3:41 PM, Ricardo Moran <[hidden email]> 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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