WM_CLASS purpose?

[Vladimir A. Pavlov]

Hi.

I'm working on a window manager and I got a few
questions concerning WM_CLASS property.

The questions are:

1. What is WM_CLASS's purpose? I thought it's to find
   X resources set by xrdb but Xrm* functions doesn't
   seem to depend on it. Is there any specific purpose,
   or does WM_CLASS have no specific purpose and just
   stores the info that other apps/users decide on how to use it?

2. Are there rules (recommendation) that an application should
   follow when setting res_name and res_class?

   For example, let's suppose I have a window manager
   somebox that has taskbar, dock, menus for starting
   applications/switching workspaces and configuration dialogs.
   What should be res_name/res_class for each of them?

   Accordng to manpage, res_name should be the application
   name and res_class should be the application class. So all
   the windows listed above should have the same
   res_name="somebox", res_class="WindowManager". But many
   apps I've seen don't seem to follow this logic. What's the
   proper way to set WM_CLASS for the windows?

Is this the appropriate mailing list to ask this question, or should
I write somewhere else (xorg-devel?)?