How to check whether the current line is a comment-only one?

[Marcin Borkowski]

Hi folks,

is there a predicate function to determine whether the line the point is
in is entirely a comment line?  I'd prefer this function to work in
various modes (for Elisp mode, it's trivial; for C, less so).

TIA,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University