X11 signal to emacs

[Perry Smith]

I'm on AIX but lets assume I'm on a "normal" platform because I'm hoping it
will be the same.

I'm using emacs (25.1) as an X11 client.

Right now, for some reason, my emacs gets stuck.  What I'd like to do is
send it a signal from a separate terminal.  I can do that but in all cases,
emacs just exits.  I've tried SIGHUP, SIGINT, and SIGTERM.

Is there a way to send a signal to emacs that emacs will catch and get out
of whatever loop it might be in at the time?  So far, I have not been able
to find a method to do that.

Thank you,
Perry