bug#24656: 25.1; Emacs leaves lock files on a CIFS share

[Paul Eggert]

On 10/11/2016 09:29 AM, Eli Zaretskii wrote:
> I thought we wanted a different character to minimize
> the risk of errors in parsing the link name.

Ah, OK, perhaps it's due to worries about interoperating with an older 
Emacs scheme that used just "USER@DOMAIN" without the trailing 
".PID:BOOT". If so, we should use some string that cannot be interpreted 
as a valid domain name by an ancient Emacs. So, how about using '..' 
instead of ':'? That is, "USER@DOMAIN.PID..BOOT". This should work since 
a valid domain name cannot contain "..".

The complete set of allowed characters here, if '..' doesn't work for 
some reason, is '(', ')', '<', '>', '[', ']', ':', ';', '@', '\', ',', 
'.', '"', according to Internet RFC 5322 section 3.2.3. Of these 
characters only '.' is allowed in a POSIX portable file name.