COM InterOp - InterOp assembly marking a char **buffer as System.IntPtr instead of out System.IntPtr

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sanjeev@securlinx.com - 10 Apr 2006 20:32 GMT

I have the following problem if referencing a COM assembly from a C#
program.
The method GetImageFrame declared as

HRESULT GetImageFrame([in] long capDeviceIndex, [out] ULONG *pSize,
[out, size_is(,*pSize)] BYTE **ppImageBuf); in the COM IDL

is displayed as GetImageFrame(int, out uint, System.IntPtr)
I expected it to be GetImageFrame(int, out uint, out System.IntPtr)

I tried changing the IL code (using ildasm, changing the fn
declaration) and using ilasm to create the new assembly). I marked the
[out] native int ppImageBuf,
as [out] native int& ppImageBuf,

However, I do not see the changes in the function declaration after
referencing the new assembly.

Does someone have a clue?

Regards,
SK

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Mattias Sjögren - 10 Apr 2006 21:31 GMT

>However, I do not see the changes in the function declaration after
>referencing the new assembly.
>
>Does someone have a clue?

Did you change all occurances of the signature? It may appear more
than once.

Mattias

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Mattias Sjögren [C# MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

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sanjeev@securlinx.com - 11 Apr 2006 03:16 GMT

Yes, there are two occurances and I change both of them. I use the
ilasm tool to create the assembly.

The (Client) project is now referencing the old and new assembly. THe
new assembly however does not reflect the modified signatures.

SK

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sanjeev@securlinx.com - 21 Apr 2006 17:21 GMT

> Yes, there are two occurances and I change both of them. I use the
> ilasm tool to create the assembly.
[quoted text clipped - 3 lines]
>
> SK

I corrected the problem that I had reported earlier. As I mentioned do
the following -

Change the IL code (using ildasm, changing the fn declaration) I
changed the
[out] native int ppImageBuf, TO
[out] native int& ppImageBuf,

Use ilasm to create a new assembly. Now in your .NET client project
refer to this new assembly after removing the reference to the old
assembly. (Because I had not removed to the reference to the old
assembly, I was still seeing it in the object browser and not the
changes I had expected to.)

SK

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COM InterOp - InterOp assembly marking a char **buffer as System.IntPtr instead of out System.IntPtr

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