rcirc-fill-column

rcirc-fill-column is a variable defined in `rcirc.el'.
Its value is

nil

• This variable may be risky if used as a file-local variable.

Documentation:
Column beyond which automatic line-wrapping should happen.
If nil, use value of `fill-column'.
If a function (e.g., `frame-text-width' or `window-text-width'),
call it to compute the number of columns.

You can customize this variable.