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From: db@helium.East.Sun.COM (David Brownell)
Newsgroups: comp.windows.x
Subject: Re: X and RPC libraries: Can they co-exist?
Message-ID: <4050@eastapps.East.Sun.COM>
Date: 24 Jan 91 17:52:08 GMT
References: <2962@hsi86.hsi.com> <62280@bbn.BBN.COM>
Sender: news@East.Sun.COM
Reply-To: db@east.sun.com (David Brownell)
Organization: Sun Microsystems, Billerica MA
Lines: 37

In article <62280@bbn.BBN.COM> fkittred@spca.bbn.com (Fletcher Kittredge) writes:
> In article <2962@hsi86.hsi.com> wright@hsi86.hsi.com (Gary Wright) writes:

> >Has anyone tried to integrate RPC mechanisms within the X toolkit
> >event loop programming model?  I am looking specifically for anyone who
> >has experience with Sun's ONC system or Apollo/HP/OSF's NCS RPC mechanisms
> >with any X toolkit.  It doesn't seem to me to be a straight forward problem
> >since both types of libraries (X & RPC) make certain assumptions about blocking
> >on sockets reads and neither was designed with the other in mind.

> OSF DCE comes with a threads package, which addresses this problem.
> 				... Sun's current thread
> implementation will be of no help since it is a user space implementation
> which blocks all threads if the current thread is waiting on a syscall.

Don't draw the conclusion that you can't use SunRPC with X toolkits
because Sun's current (4.x) LWP library isn't kernel-based; that would be
wrong.  SunRPC was designed with the knowledge that it would need to be
integrated with other event loops; I know of several tools that talk to
each other using SunRPC.

Using only public interfaces -- look for documentation on custom versions
of svc_run(), which is the primary server side component to block -- it's
easy to have X applications act as SunRPC servers, so that incoming RPC
requests are dispatched just like incoming X protocol messages are.  Blocking
as an RPC client can usually be minimized or even avoided; otherwise, it's
just another case where an X application needs to disable input temporarily.

The current XView sources already have that server side support, if you
request it by calling notify_enable_rpc_svc(TRUE).  It's not tough to do
the same with raw Xlib or intrinsics, either, but does require grokking
both toolkit and SunRPC documentation.  There's no need to wait for a new
networking or OS framework unless you really want to.

- Dave

One of the Million monkeys ... see, here's my keyboard!