I think the latest merged pull request takes care of this https://github.com/kbilsted/NotepadPlusPlusPluginPack.Net/commit/a9c44746380ca3af7a147a5466342c632e2b0d80
happy to hear your thoughts :)

After discussing with the author of Scintilla and not being able to reach the author of N++ it seems no one is interested in cleaning up the zest pool of mess called the api to N++ and Scintilla. A lot of really nice stuff could come out of taking a more structured/generative approach benefiting plugin packs of all languages. But no interest is to be traced from those authors…

As fas as I can tell (I didn’t try your version!) you will have the following problems with your version :

• Your plugin will register its functions array but you will not correctly receive the notifications from npp/scintilla (all header.code will be at 0)
• Calls to sendmessage might cause the program to freeze as stated in the pinvoke page :

2) NEVER use "int" or "integer" as lParam. Your code WILL crash on 64-bit windows. ONLY use IntPtr, a "ref" structure, or an "out" structure.

3) NEVER use "bool", "int", or "integer" as the return value. Your core WILL crash on 64-bit windows. ONLY use IntPtr. It's not safe to use bool - pInvoke cannot marshal an IntPtr to a boolean.

regards

You will also need to make the following modification for your C# plugin to work on x64 :

• Change from int to IntPtr in the notification structure (compare what you have to what’s below)

    [StructLayout(LayoutKind.Sequential)]
    public struct Sci_NotifyHeader {
        /* Compatible with Windows NMHDR.
         * hwndFrom is really an environment specific window handle or pointer
         * but most clients of Scintilla.h do not have this type visible. */
        public IntPtr hwndFrom;
        public IntPtr idFrom;
        public uint code;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct SCNotification {
        public Sci_NotifyHeader nmhdr;
        public int position; /* SCN_STYLENEEDED, SCN_MODIFIED, SCN_DWELLSTART, SCN_DWELLEND */
        public int ch; /* SCN_CHARADDED, SCN_KEY */
        public int modifiers; /* SCN_KEY */
        public int modificationType; /* SCN_MODIFIED */
        public IntPtr text; /* SCN_MODIFIED, SCN_USERLISTSELECTION, SCN_AUTOCSELECTION */
        public int length; /* SCN_MODIFIED */
        public int linesAdded; /* SCN_MODIFIED */
        public int message; /* SCN_MACRORECORD */
        public IntPtr wParam; /* SCN_MACRORECORD */
        public IntPtr lParam; /* SCN_MACRORECORD */
        public int line; /* SCN_MODIFIED */
        public int foldLevelNow; /* SCN_MODIFIED */
        public int foldLevelPrev; /* SCN_MODIFIED */
        public int margin; /* SCN_MARGINCLICK */
        public int listType; /* SCN_USERLISTSELECTION */
        public int x; /* SCN_DWELLSTART, SCN_DWELLEND */
        public int y; /* SCN_DWELLSTART, SCN_DWELLEND */
        public int token; /* SCN_MODIFIED with SC_MOD_CONTAINER */
        public int annotationLinesAdded; /* SC_MOD_CHANGEANNOTATION */
        public int updated; /* SCN_UPDATEUI */
        public int listCompletionMethod; /* SCN_AUTOCSELECTION, SCN_AUTOCCOMPLETED, SCN_USERLISTSELECTION */
    }

• modify your sendmessage P/Invoke to NO LONGER use int or bool (see this page); instead use the following signature :

[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);

For information, i post the modifications on my end to make it work :
https://github.com/jcaillon/3P/commit/63d0f408489605cbaefe50d4565515ef70959e2e#diff-009e4601aad253f284d4f65fdba02937
https://github.com/jcaillon/3P/commit/63d0f408489605cbaefe50d4565515ef70959e2e#diff-e465f2e4346ecedd11f61657df6d2415
https://github.com/jcaillon/3P/commit/63d0f408489605cbaefe50d4565515ef70959e2e#diff-a583b7dff72eb31fe063a30da70a3313

En last thing, I do use UnmanagedExport version 1.2.7.

https://www.nuget.org/packages/UnmanagedExports

the latest version there is 1.2.7. The followup nuget package with a somehow different structure is available in version 1.5 at:

https://www.nuget.org/packages/DllExport/

    public void Add(FuncItem funcItem)

and
public void RefreshItems()

in class FuncItems in NppPluginNETHelper.cs, like:

        IntPtr ptrPosNewItem = (IntPtr)((int)newPointer + oldSize);

So the cast to int from type IntPtr shortens the pointer for X64, see e.g.

https://blogs.msdn.microsoft.com/jaredpar/2008/11/11/properly-incrementing-an-intptr/
or
https://stackoverflow.com/questions/1866236/add-offset-to-intptr

Does anyone know of a shared/maintained repo for this project?

@Kasper-Graversen has done some great work updating it. https://github.com/kbilsted/NotepadPlusPlusPluginPack.Net

As to your other questions, I can’t say since I don’t use C#.