COM Interface

[PureGuy]

As noticed in my other topic: http://www.purebasic.fr/english/viewtop ... =5&t=59640
There is something weird with passing parameters to COM objects via interfaces.

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HRESULT AddToSnapshotSet(
  [in]   VSS_PWSZ pwszVolumeName,
  [in]   VSS_ID ProviderId,
  [out]  VSS_ID *pidSnapshot
);

How comes that C can call the method using 3 parameters and PB x86 has to use 4.

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AddToSnapshotSet(pwszVolumeName, ProviderId_Part1.q, ProviderId_Part2.q, *pidSnapshot)

Also interesting http://vortex.masmcode.com/files/vscopy101.zip

from \Windows7\Source\vscopy.asm

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coinvoke    pBackupComponent,IVssBackupComponents,AddToSnapshotSet,\
                buffer,0,0,0,0,pSnapShotId
                

from \Windows7\Source\vscopy.inc

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MACRO coinvoke

MARG ppv :REQ,interface :REQ,member :REQ,params :VARARG

    FOR arg IN: params REV DO
    
        push arg

    ENDM

    mov     eax,[ppv]
    push    eax
    mov     eax,DWORD PTR [eax]
    call    [eax+&interface.&member]
    
ENDM

So how to know, how to pass parameters using PB x86?
And why does it works as expected for PB x64?

[Fred]

Well, VSS_ID is a GUID (enhance a 128-bit number) and PB doesn't support this natively. You can define it as you did for x86 (with double quad). On x64, it's just by ref for anything above 64 bit IIRC

[PureGuy]

Thanks for the fast answer.

Yes, it seems using 2 quad is working