Re: Feature suggestion: server sockets

[Richard Stallman]

This is a useful feature, and a clean Lisp interface.
I see a couple of possible gaps in the implementation, though.

Doing this from Emacs itself is cleaner than running an actual
subprocess like emacsserver to do the job.  But the subprocess runs
all the time, in parallel with Emacs, while this code seems to be able
to accept a server connection only inside wait_reading_process_input.
If Emacs is running a Lisp program for a long time, it may go for a
long time without ever calling wait_reading_process_input.  This could
conceivably mean that Emacs takes too long to respond and the request
fails.

Can you make connection acceptance happen in response to a signal
such as SIGIO, or make it happen in an alarm that happens frequently?
(Such as the one used to poll for available terminal input.)
The actual running of the filter function would have to wait until
wait_reading_process_input, of course.  Something like this already
happens with sentinels, I recall.

One other point: this seems to be designed to work with PF_INET
sockets only.  If you look at emacsclient, you'll see it uses either a
PF_UNIX socket or SYSVIPC.  To make server sockets replace
emacsserver, they would have to support both PF_UNIX sockets and
SYSVIPC (unless SYSVIPC is obsolete nowadays and all systems support
sockets).