To write a plug-in DLL, you need to be familiar with the following:
  1. The C programming language. There is no language support for the &os2; Pascal dialects at this point.

  2. Presentation Manager programming. A widget class is essentially a PM window class (see "Terminology").

    If you haven't written a PM window class from scratch before, don't worry. The samples will guide you, and it isn't that difficult. If you know what a window procedure is, and if you know the difference between an owner and a parent window and WinSendMsg and WinPostMsg, you should be fine. Of course, the more you know, the better.

  3. You should know what a DLL is, when and why they are used, and why a DLL is not a process. ;-)
Now for the good news: You do not need to know WPS and/or SOM programming, which should be a great relief to many contributors.

Also, you can use any C compiler you want. Even EMX/GCC should do. The only &xwp; code that is required are the headers that you are including, which now come with the &xwp; binary distribution (in the toolkit directory).

If you get lost, you can always download the complete &xwp; source code, where you will find the source code for the standard plug-in DLLs which come with &xwp; (the window list and the clock and memory monitors), which show you in detail how it's done.