Re: line-number-display-limit-width

[martin rudalics]

> using emacs 21.3 on windows:
>
> the help file claims I can set var "line-number-display-limit-width", but
> there is no such variable.

With Emacs 21.3 typing C-h v RET line-number-display-limit-width RET
should give you

line-number-display-limit-width's value is 200

Documentation:
*Maximum line width (in characters) for line number display.
If the average length of the lines near point is bigger than this, then the
line number may be omitted from the mode line.

> do I need to setup that variable?

Only if computing the line-number slows down Emacs.  With Emacs 22.1
this variable is customizable.

> I saw the linum.el, but it displays line numbers in the buffer instead of
> the mode line at the bottom.

Indeed.  linum.el is not related to this.