Question

I have some C code which will be called from C# using P/Invoke. I am trying to define an C# equivalent for this C function.

SomeData* DoSomething();

struct SomeData
{
    ...
}

How do I import this C method to C#? I am having trouble defining the return type of the function.

EDIT:
i had a bunch of functions to import. This is one which had me stuck.

[DllImport("SomeDll.dll")]
public static extern IntPtr DoSomething();

I thought about using IntPtr, even if its the right way what after that?

Answer 1

I’m not quite sure I understand your question but I’ll give a shot at answering it. You need to define the structure that is being returned from your C function and use Marshal.PtrToStructure to use the returned structure.

[DllImport("SomeDll.dll")]
public static extern IntPtr DoSomething();

public struct SomeData
{
    //...
}

//code to use returned structure
IntPtr result = DoSomething();

SomeData structResult = (SomeData)Marshal.PtrToStructure(result, typeof(SomeData));