(setq debug-process-io 1) helps a lot.  I see now that when I press Done, gnuserv fails in send_string with a bad file descriptor.  In my case the descriptor is 5.

On Wed, Apr 12, 2017 at 8:39 AM, Raymond Toy <toy.raymond@gmail.com> wrote:
I built the ToT version on Ubuntu 14.04 and everything seems to be working fine except for one thing.

I start xemacs, and the M-x gnuserv-start.  In a terminal, I run "gnuclient file".  Edit the file in a new window as usual and press the Done button.  Window is closed and everything seems fine, but in the main xemacs window, the minibuffer says that gnuserv exited and to M-x gnuserv-start again.

This didn't used to happen.  Can't figure out why gnuserv is exiting in this way.  Any tips on figuring this out?