From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from smtp1.rz.uni-karlsruhe.de (Debian-exim@smtp1.rz.uni-karlsruhe.de [129.13.185.217])
	by krisdoz.my.domain (8.14.3/8.14.3) with ESMTP id o8PLcEcR026054
	for <discuss@mdocml.bsd.lv>; Sat, 25 Sep 2010 17:38:14 -0400 (EDT)
Received: from hekate.usta.de (asta-nat.asta.uni-karlsruhe.de [172.22.63.82])
	by smtp1.rz.uni-karlsruhe.de with esmtp (Exim 4.63 #1)
	id 1OzcRh-0004Py-0I; Sat, 25 Sep 2010 23:38:13 +0200
Received: from donnerwolke.usta.de ([172.24.96.3])
	by hekate.usta.de with esmtp (Exim 4.71)
	(envelope-from <schwarze@usta.de>)
	id 1OzcRg-0006Rb-VK
	for discuss@mdocml.bsd.lv; Sat, 25 Sep 2010 23:38:12 +0200
Received: from iris.usta.de ([172.24.96.5] helo=usta.de)
	by donnerwolke.usta.de with esmtp (Exim 4.69)
	(envelope-from <schwarze@usta.de>)
	id 1OzcRg-0001Sr-UG
	for discuss@mdocml.bsd.lv; Sat, 25 Sep 2010 23:38:12 +0200
Received: from schwarze by usta.de with local (Exim 4.71)
	(envelope-from <schwarze@usta.de>)
	id 1OzcRg-00048g-TJ
	for discuss@mdocml.bsd.lv; Sat, 25 Sep 2010 23:38:12 +0200
Date: Sat, 25 Sep 2010 23:38:12 +0200
From: Ingo Schwarze <schwarze@usta.de>
To: discuss@mdocml.bsd.lv
Subject: Re: .Fn _* issue
Message-ID: <20100925213812.GE23359@iris.usta.de>
References: <20100925063547.GB14869@bramka.kerhand.co.uk>
X-Mailinglist: mdocml-discuss
Reply-To: discuss@mdocml.bsd.lv
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20100925063547.GB14869@bramka.kerhand.co.uk>
User-Agent: Mutt/1.5.20 (2009-06-14)

Hi Jason,

Jason McIntyre wrote on Sat, Sep 25, 2010 at 07:35:23AM +0100:

> hi. the source, from cacheflush(3):
> 
> 	.Sh SYNOPSIS
> 	.In machine/sysarch.h
> 	.Ft int
> 	.Fn cacheflush "void *addr" "int nbytes" "int cache"
> 	.Ft int
> 	.Fn _flush_cache "char *addr" "int nbytes" "int cache"
> 
> formats as:
> 
> 	SYNOPSIS
> 	     #include <machine/sysarch.h>
> 
> 	     int
> 	     cacheflush(void *addr, int nbytes, int cache);
> 
> 	     int
> 	     _flush_cache(char *addr, int nbytes, int cache); 
> 
> so the issue is the initial `_' in _flush_cache. it's formatted in a
> different font to the rest of the function name (you can see this best
> on a terminal).

As Kristaps said, the first underscore is rendered underlined.
Apparently, that's the default interpretation of "_\b_".
The second understore, though, is rendered bold, even though
it's physically the exact same sequence of charachters, "_\b_".
Probably, that happens because the preceding 'h' character
is bold and not underlined.  If i change that 'h' to underlined,
the second underscore becomes underlined, too.

Thus, i agree with Kristaps that i see nothing we could do about it.
It's not a mandoc bug, maybe not even a bug at all, but a limitation
of backspace encoding for bold and underline.

> this is a long standing bug that we always had in old groff, which
> really annoyed me. new groff fixed it.

Not really.  What happens is that groff-1.20.1 uses ANSI encoding,
not backspace encoding for bold and underline, and in ANSI encoding,
that limitation does not exist.  In ANSI encoding, the bold underscore
is "\e[1m_" while the underlined underscore would be "\e[4m_",
the "\e" representing the escape character (ASCII 0x1b).

Yours,
  Ingo
--
 To unsubscribe send an email to discuss+unsubscribe@mdocml.bsd.lv