bug#25214: #25214 26.0.50; Interacting with user from threads other than the primary

[Eli Zaretskii]

> From: Zhang Haijun <ccsmile2008@outlook.com>
> CC: "25214@debbugs.gnu.org" <25214@debbugs.gnu.org>
> Date: Thu, 7 Feb 2019 14:56:22 +0000
> 
> 
> Sorry for my poor English and poor expression. I mean a data channel, for 
> example a pair of fd created by pipe() or a pair of sockets created by 
> socketpair(). producer-consumer model.
> 
> > If another thread writes to some fd, it means the main thread is not
> > running, so it cannot receive the event, even if we did find the way
> > of having an fd which can be read by one thread and written by all the
> > others.
> 
> Another thread send a input request and then be blocked on a lock(for 
> example, keybord lock, one lock per thread). The main thread(or keybord 
> sheduler thread) then can wake up one thread and give keybord to it.

Unless the thread that listens to these requests is never blocked, I
don't see how this could work.

And in any case, what should a non-main thread do if it wants to ask a
question?  Asking a question involves displaying the question before
reading the answer.  You only talked about the second part.