because i often hide the ckvwm panel, so I want to set a xlabel indicating which virtual desktop I am in. But I find that ckvwm does not "export" current evars. How can I implement this feature? By the way, I know some other vwm do provide such functionality, but I dont want to make a switch yet. Thanks.

Very easy with rabidvwm. You could sort of work around it with ckvwm, but it'd just be easier to switch.

What he said.