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a good gameplay is a right combination between performance and features.

Here is a simple struct with two values and a C function to pass a pointer.

extern "C" { struct AddStruct { int one; int two; }; int APIENTRY STestCallAddPointer(AddStruct* values) {return values->one + values->two;}; }

You may need to define this in a DEF file like this:

STestCallAddPointer @1

Finally, the C# code. Here is where you need to define your struct and the functions you will use. These go inside of your C# class. They define the function to call, but 'extern' says this function is defined OUTSIDE of this class. In the example, the function is defined in a DLL called MFCDll.dll.

When laying out the struct, you need to use the C# equivalent data types for the C data type. The below example I used Int32 for C's int. If you need help with this, there are mapping tables which tell you what types to use. I can post a link if you are interested.

[StructLayout(LayoutKind.Sequential)] public struct AddStruct { public Int32 one; public Int32 two; } [DllImport("MFCDll.dll")] public static extern int STestCallAddPointer(IntPtr values);

And finally...to call the function you need to create your struct, set the values, convert to a passable pointer, and then call the function with the pointer buffer.

// Testing pointer AddStruct values; values.one = 100; values.two = 200; int size = Marshal.SizeOf(values); IntPtr buffer = Marshal.AllocCoTaskMem(size); Marshal.StructureToPtr(values, buffer, false); valueTest = STestCallAddPointer(buffer); Marshal.FreeCoTaskMem(buffer);

The resulting value for valueTest is 300.

I do not know if it is possible to change some values from the C function and have C# get this updated value.

Hopefully this helps you. Let me know if you have any questions. And you just helped me add another test case to my research/study application. Thanks!

That's pretty much how I did it. I found something relevant on googlegroups. Following the examples there I came up with this way of declaring the C function in C# (which didn't work):

public static extern int ManyMouse_PollEvent([MarshalAs(UnmanagedType.LPStruct)] ManyMouseEvent MouseEvent);

Then I found the method you're using - a IntPtr argument - which finally worked.

Then you posted =]

I guess I have it figured out, however I'm having issues with the C function itself.

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a good gameplay is a right combination between performance and features.

When you use the library you have to initialize it first with ManyMouse_Init(), the function should return at least 1 (if you have a mouse connected).

this is what I'm using as a test

#include <iostream> #include "manymouse.h" using namespace std; int main () { ManyMouseEvent MouseEv; int result = ManyMouse_Init(); cout << "ManyMouse init result: " << result ; int Enter; cin >> Enter; return 0; }

For some reason I keep getting 0 from ManyMouse_Init() (which means it can't see a mouse). In another project the function works ok (the number of mouse devices returned is correct). It's probably some IDE settings, I don't know. I'll give it another try tomorrow. If you want to play with it and get it figured out let me know. I'm sure there's an obvious mistake somewhere.

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a good gameplay is a right combination between performance and features.

Are you running in Windows XP? I looked at some documentation and it stated the init call will return 0 if it's not running on XP. Not sure about Vista.

It's strange how it will work in one project and not in another. Maybe use the working project as a baseline for moving forward on the other project.

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a good gameplay is a right combination between performance and features.

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a good gameplay is a right combination between performance and features.

http://calinnegru.googlepages.com/downloads

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a good gameplay is a right combination between performance and features.