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How to type cast from IntPtr
f#

I can't manage to rewrite a simple piece of C# code in F# even after many hours of reading and surfing. In the end, I gave up. But I would still like to understand how the following code should be written in F#.

C# code:

IntPtr p= IntPtr.Zero;

tlb.GetLibAttr(out p);

try

{

TYPELIBATTR* attr = (TYPELIBATTR*)p;

...

Where GetLibAttr is:

System.Void GetLibAttr(System.IntPtr ppTLibAttr)

Member of System.Runtime.InteropServices.ComTypes.ITypeLib

I had:

let mutable p:System.IntPtr = System.IntPtr.Zero

tlb.GetLibAttr(&p);

let attr = (box p) :?> (TYPELIBATTR)

But this fails with a run time exception.

Thanks,

James

.

Suggestive code (I have not tried it really):

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type Foo = struct end
let x = System.IntPtr.Zero 
let y : nativeptr<Foo> = NativeInterop.NativePtr.ofNativeInt x

See also

[link:msdn.microsoft.com]

By on 11/23/2009 2:31 PM ()

thanks Brian, you are a star.

Here is the working code:

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    let mutable x = System.IntPtr.Zero 

    pLib.GetLibAttr(&x);

    let y  = NativeInterop.NativePtr.of_nativeint<TYPELIBATTR> x

    let z = NativeInterop.NativePtr.read y
By on 11/24/2009 1:16 AM ()

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