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    <p>You'll probably want to use <a href="http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.marshal.getdelegateforfunctionpointer.aspx" rel="noreferrer"><code>Marshal.GetDelegateForFunctionPointer</code></a>:</p> <ol> <li>Create a delegate type that matches the signature of the native function, keeping in mind the right way to marshal types and using <a href="http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.marshalasattribute.aspx" rel="noreferrer"><code>MarshalAs</code></a> as needed</li> <li>Communicate the native function pointer from your native code to your C# code however you can (in your case, it looks like you can use your COM -> C# connection)</li> <li>Use <code>Marshal.GetDelegateForFunctionPointer</code> to turn the pointer into a C#-callable delegate</li> <li>Invoke the delegate with your parameters</li> </ol> <p>Junfeng Zhang has an example of doing this <a href="http://blogs.msdn.com/b/junfeng/archive/2004/07/14/181932.aspx" rel="noreferrer">here</a>.</p> <p>Note the restrictions mentioned on MSDN:</p> <blockquote> <p>The GetDelegateForFunctionPointer method has the following restrictions:</p> <ul> <li>Generics are not supported in interop scenarios.</li> <li>You cannot pass an invalid function pointer to this method.</li> <li>You can use this method only for pure unmanaged function pointers.</li> <li>You cannot use this method with function pointers obtained through C++ or from the GetFunctionPointer method.</li> <li>You cannot use this method to create a delegate from a function pointer to another managed delegate.</li> </ul> </blockquote> <p>The part about C++ is likely referring to function pointers for class methods. This should still work for global functions. </p>
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    1. COIn step 2 will the function pointer initially arrive in C#-land as an IntPtr?
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    2. COTo get the pointer from C/C++ to C#, it will be marshaled. Yes, C/C++ pointers are represented as a C# `IntPtr` whose size is platform-specific.
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    3. COI'm probably doing something dumb. The C++ compiler complains that it can't convert my parameter from voic(__cdecl*)(UINT) to long (the method takes an IntPtr in C#). Also, Zhang's example involves a C++ function pointer retrieved in C# not one retrieved from C++...
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