Re: Possessive apostrophe with singular nouns ending in "s"

[Deniz Dogan]

On 2012-02-23 18:48, Glenn Morris wrote:
> A critical question. What is the standard form in GNU manuals for using
> the possessive apostrophe with singular nouns ending in "s"?
>
>    This is one of Emacs's most important features.
>
> or
>
>    This is one of Emacs' most important features.
>
> Currently there are ~ 46 instances of the former in the manuals, and 63 of
> the latter. I favour the former.

What does grammar say?  Is it a corner-case?  Does it differ depending 
on locale?