Re: [BUG] "\fC" macro in ox-man.el [9.6.15 (release_9.6.15 @ /usr/share/emacs/29.2/lisp/org/)]

[Xiyue Deng <manphiz@gmail.com>]

Hi Ihor,

Ihor Radchenko <yantar92@posteo.net> writes:

> Xiyue Deng <manphiz@gmail.com> writes:
>
>> (This was first reported to Emacs at
>> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=69483)
>>
>> "mu4e"[1] (a popular Emacs mail client) uses Org to generate its
>> manpages.  However, the generated output contains macros that are not
>> understood by groff.  After some debugging, Jeremy traced this back to
>> the macro "\fC" used in ox-man.el[2].  Git history shows that this may
>> have been there since the beginning.  We tried to find a documentation
>> for the "\fC" macro but has not been able to find one.  Jeremy suggests
>> that "C" may be an old alias for Courier, and if that's the case it
>> should be changed to "\f[CR]".  Would be great if Org people can
>> confirm.
>
> This is not an unknown problem. AFAIU, the \fC macro is widely used for
> troff, although it is not supported by groff. Check out the ongoing
> discussion at https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1049968#15
>
> They suggest the following instead of \fC:
>
>    The best solution known to me is to use an extension to the man(7)
>    language.  It first appeared in Ninth Edition Unix (1986) and was
>    adopted by a groff release in 2009.  That is the `EX`/`EE` macro pair,
>    which sets a monospaced display.  (In other words, filling is disabled
>    and a monospaced font selected if necessary.)

I'm not very familiar with roff so my understanding may be off.
According to the `Safe subset' section in man(7), they mentioned the
following:

,----
| Font changes (ft and the \f escape sequence) should only have the
| values 1, 2, 3, 4, R, I, B, P, or CW (the ft command may also have no
| parameters).
`----

Does it mean `\fC' should be replaced by `\f[CW]'?

Also CCing Jeremy who may have a better idea on how this should be
handled.

-- 
Xiyue Deng