How to use Delegates

[physics-sec]

Hi!

I would really like to use Delegates and I am not sure how to do it in Boo.

My goal is to call unmanaged functions having their return type, their params and a pointer to them in unmanaged memory (like a DLL).
Here there is an example on how I use them in C#:
First, I define the delegate:

[UnmanagedFunctionPointer(CallingConvention.StdCall)]
public delegate NTSTATUS NtCloseDelegate(
    IntPtr ObjectHandle
    );

Then, having a pointer to this function, I call it using the delegate:

    // memAddr is a pointer to unmanaged memory where NtClose is defined.

    NtCloseDelegate assembledFunction = (NtCloseDelegate)Marshal.GetDelegateForFunctionPointer(memAddr, typeof(NtCloseDelegate));

    NTSTATUS result = (NTSTATUS)assembledFunction(MyObjectHandle);

That's it!

I searched the repo how to use delegates and all I could find is this way to create a delegate:

myDelegate as Delegate

I also searched the Wiki but couldn't find any references. (If I succeed, I would love to write an entry on the Wiki on how to use Delegates)

Thank you in advance! 😄

[masonwheeler]

Much like how in C#, you define a delegate type as a method signature with the delegate keyword, in Boo you define it with the callable keyword. Thus:

[UnmanagedFunctionPointer(CallingConvention.StdCall)]
public callable NtCloseDelegate(ObjectHandle as IntPtr) as NTSTATUS

And then you use Marshal.GetDelegateForFunctionPointer as usual, except it's probably better to use the Generic version rather than casting:

var assembledFunction = Marshal.GetDelegateForFunctionPointer[of NtCloseDelegate](memAddr)

[physics-sec]

Amazing! It works!
Thank you so much for the quick answer! 😄