CODEWITHSUNDEEP
vba64-bitvsto
Chang
Chang

Reputation: 179

Is handle always 32bit on both 32bit and 64bit platforms?

I need to obtain the handle of Excel 2016 64bit.

But Application.Hwnd returns a long , and there is no Application.HwndPtr.

Is it reliable?

If it's reliable, why Microsoft add Application.HInstancePtr instead of use the old Application.HInstance on 64bit platforms?

Is it possible for a window handle larger than 32bit?

Upvotes: 1

Views: 450

Answers (1)

Hans Passant
Hans Passant

Reputation: 941635

It is fine, the OS ensures that a window handle can never overflow a 32-bit value. You can never have more than 65535 windows on a desktop so it is quite easy to do. That it works this way is something you can see in COM interop declaration for a remotable window handle, visible in the WTypes.idl SDK file:

typedef union _RemotableHandle switch( long fContext ) u
{
    case WDT_INPROC_CALL:   long   hInproc;
    case WDT_REMOTE_CALL:   long   hRemote;
} RemotableHandle;

typedef [unique] RemotableHandle * wireHWND; 
typedef [unique] RemotableHandle * wireHMENU;
// etc..

Note how it is long for an out-of-process call, a 32-bit value.

A HINSTANCE is a very different kind of handle, a kernel handle, it certainly is 64-bit value under the hood. Equal to the base address in memory of the module, so they were forced to add this property.

Upvotes: 3

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