When does XGetCommand(.) work???

[Thomas Lübking]

I'm trying to query argv[0]  by WId (on user interaction, selecting window 
similar to xwininfo)
However this does not work in many cases (it does for e.g. xterm or juk, but 
not for konsole, OOo, kwrite, gnome-ding, ...), returned Status is 0.

XGetClassHint(.) however works everytime, while unfortunately the first char 
of res_class seems to be upcased, so i cannot detect argv[0] case correct (i 
could assume that the first char needs to be lowercased, but  hope for a 
better way)

so
1. is there another way to detect argc[0] i missed
2. if not, what's critical about XGetCommand(.) so that it does not work in 
all cases

Thanks,
Thomas