Re: Asynchronous DNS

[Lars Magne Ingebrigtsen]

Paul Eggert <address@hidden> writes:

> Lars Magne Ingebrigtsen wrote:
>> 2) Use one of the newer async C resolver libraries.  This would not be
>> available on all platforms, and would be Yet Another Dependency which
>> I'm sure everybody would rather that we avoid.
>
> Nevertheless, this sounds like the most promising approach. Why
> reinvent the wheel? Platforms lacking the library will be no worse off
> than they are now.
>
> Do you consider GNU adns to be one of the "newer" libraries? If not,
> what problems do you see with GNU adns?

I haven't looked closely at any of the asynchronous C libraries, because
I assumed that it was off the table.  But if it's fine to add another
(optional) C library to the Emacs build, then I'm up for investigating
further and taking a stab at implementing it.

The most well-distributed C-level libraries for async DNS seem to be
adns, c-ares and firedns, at least on Linux systems.  adns has no
documentation, but has a very well-commented C header file, and looks,
at first blush, to provide a sane interface.

firedns looks pretty abandoned.  c-ares seems sane and has
documentation:

https://github.com/c-ares/c-ares

udns seems even better:  http://www.corpit.ru/mjt/udns.html
Unfortunately, it doesn't look like it's available on Debian, for
instance, which limits its practicality.

I have no experience with either of these libraries in practice...
Anybody have any input here?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no