Subject: Re: bug#22303: 24.5; toggle-truncate-lines not mentioned in docstring for truncate-lines nor in elisp manual

From: Eli Zaretskii <[email-masked]>
Date: Mon, 04 Jan 2016 19:11:31 +0200

> From: phs <[email-masked]>
> Date: Mon, 4 Jan 2016 10:30:17 +0100
> 
> In general, changing the value of `truncate-lines' should be done via 
> `toggle-truncate-lines' not by `(setq truncate-lines ..)'
> 
> However the documentation string for `truncate-lines' does not mention 
> the existence of `toggle-truncate-lines', nor is it mentioned in the
> elisp manual (section "37.3 Truncation").
> 
> It seems that modifying `truncate-lines' with just `(setq ..)' may 
> suffer from redisplay problems, see 
> http://emacs.stackexchange.com/questions/19228 for a way to trip the 
> problem from emacs -Q.

Thanks for pointing this out.

The answers on stackexchange are incorrect: there's nothing wrong with
setting 'truncate-lines' directly.  The situation described there
revealed a bug, which I just fixed for the next release.

I see no need to change the documentation in this regard.