Hi Rich, Vincent,

> Date: 2026-11-11 22:37:42-0500
> From: Rich Felker <dalias@libc.org>
>
> On Thu, Nov 12, 2026 at 04:29:29AM +0100, Vincent Lefevre wrote:
> > On 2026-11-11 21:53:39 -0500, Rich Felker wrote:
> > > That's the whole reason '$' was chosen: POSIX doesn't define the
> > > behavior (since a "shall" is violated) so the implementation is free
> > > to define a behavior here. The behaviors for the portable base64
> > > character set documented in POSIX uses only 2 characters as salt
> > > (insufficient) and the common agreed-upon definition for how they are
> > > used is as salt for the classic DES-based password hash.
> > 
> > But the behavior is completely out of scope of POSIX.
> 
> Yes. And that's allowed because POSIX does not define the behavior but
> leaves it undefined. I'm not sure if you're objecting to something
> here or questioning how it should be documented or something else..?

Yeah, I think it'd be okay to document that this is an extension to
POSIX.  Perhaps, we could add this:

	@@ -111,6 +111,9 @@ .SH ATTRIBUTES
	 .BR crypt_r ()
	 T}     Thread safety   MT-Safe
	 .TE
	+.SH VERSIONS
	+While POSIX only specifies the DES algorithms for these functions,
	+all systems implement several other algorithms.
	 .SH STANDARDS
	 .TP
	 .BR crypt ()



Have a lovely day!
Alex

> 
> Rich

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