Re: [PATCH v2 1/2] Add CTYPE defines for various sets of characters.

Alejandro Colomar via Mutt-dev <[email protected]> Wed, 5 Aug 2026 21:36:22 +0200
Newsgroups	gmane.mail.mutt.devel
Message-ID	<anOQDB08K3KngNCF@devuan>
Hi Steffen,

> Date: 2026-08-05 18:30:05+0200
> From: Steffen Nurpmeso <[email protected]>
>
> Alejandro Colomar via Mutt-dev wrote in
>  <anMoJ15bY0AGDFyK@devuan>:
>  |> Date: 2026-08-05 11:37:46+0800
>  |> From: "Kevin J. McCarthy" <[email protected]>
>  ...
>  |>>> +#define CTYPE_PFCHAR_C       CTYPE_ALNUM_C "._-"    // POSIX.1-2008 \
>  |>>> portable
>  |>>> +                                                    // filename \
>  |>>> character set
>  |>> 
>  |>> Actually, that was already true as of POSIX.1-2001 (Issue 6); the first
>  |>> modern-day POSIX, where POSIX and SUS (the Single UNIX Specification)
>  |>> were unified
>  |>> 
>  |>> I suspect this was already true way earlier, since I see a reference to
>  |>> the 'portable filename character set' in XPG Issue 4 (v2) (from which
>  |>> modern-day POSIX derives).
>  |>> <https://pubs.opengroup.org/onlinepubs/009656499/toc.pdf#page=423>
>  |>> I don't see the the definition of the p.f.c.s. in that document, because
>  |>> it was in a separate volume, and I can't find it.  It's also difficult
>  |>> to find older standards, unless you know where they are.  :)
> 
> You need an OpenGroup.org/austin/login.html.  In Issue 4 version
> 2 from 1994 there is

Thanks!  I've been able to find it, as 'Single UNIX Specification,
Version 1 Document Set (UNIX 95)'.

Is XPG Issue 4 (v1) and Issue 3 there?  I can't find them.  What are the
magic keywords to find them?  :)


Have a lovely day!
Alex

>   portable filename character set
>   The set of characters from which portable filenames are
>   constructed. For a filename to be portable across
>   implementations conforming to this document set and the ISO
>   POSIX-1 standard, it must consist only of the following
>   characters:
>   A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
>   a b c d e f g h i j k l m n o p q r s t u v w x y z
>   0 1 2 3 4 5 6 7 8 9 . _ -
>   The last three characters are the period, underscore and hyphen
>   characters, respectively. The hyphen must not be used as the
>   first character of a portable filename. Upper- and lower-case
>   letters retain their unique identities between conforming
>   implementations. In the case of a portable pathname, the slash
>   character may also be used.
> 
>  |> Okay, I'll just leave it as "portable filename character set" in the
>  |> comment then.
>  |> 
>  |>> LGTM.
>  ..
> 
> I love this standard really.  Different to ISO C23 it has
> wcwidth() because it has terminals, and the word "directory"
> occurs more than once, and if via "path"name as above.  (Though
> one of the three "path"s in ISO C23 refer to a search path, too.)
> 
> --steffen
> |
> |Der Kragenbaer,                The moon bear,
> |der holt sich munter           he cheerfully and one by one
> |einen nach dem anderen runter  wa.ks himself off
> |(By Robert Gernhardt)

-- 
<https://www.alejandro-colomar.es>
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