Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uunet!inkwell!ivan!jhc
From: jhc@ivan.uucp (James H. Coombs)
Newsgroups: comp.lang.c++
Subject: Re: C++ classes for Sun RPC
Message-ID: <54465@inkwell.UUCP>
Date: 25 Jun 91 15:32:04 GMT
References: <1991Jun19.192025.14683@colorado.edu>
Sender: news@inkwell.UUCP
Reply-To: jhc@ivan.UUCP (James H. Coombs)
Organization: IRIS - Brown University
Lines: 72

In article <1991Jun19.192025.14683@colorado.edu> jeffm@noisette.colorado.edu (Jeff McWhirter) writes:
>We have a need for  an   O-O  rpc mechanism in C++ for
>Sun RPC.  It would be nice to support blocking and non-blocking calls,
>xdr routines for passing data, ...?
>It  would also be nice if something like this has been done so we won't
>have to do it.
>Has anyone heard  of or built  such a mechanism???

I have developed an RPC++ on top of Sun's RPC.  RPC++ consists of two
major components:

	1. A C++ class definition parser generates a full set of XDR
	routines.  This set includes both the pointer and reference xdr
	routines.  It supports multiple inheritance.  A keyword can be
	applied to class fields that should not be transported.  Etc.

	2. I revised rpcgen to generate C++ classes and method
	implementations.  To implement a server, the developer uses the
	standard RPC program syntax, compiles the RPC program with the
	revised rpcgen, and subclasses the generated server/client.
	The C++ classes then have such methods as ClntInit/SvcInit and
	ClntTerm/SvcTerm.  Given a method such as RegisterQuery, the
	client simply invokes the method RegisterQuery with the C++
	Query object; the server overrides the base class and
	implements any required functionality.

Other features:

	1. RPC++ supports both blocking and asynchronous I/O.  There is
	a separate library to implement async. I/O for Motif
	applications.

	2. Built-in error handling.  I also developed an error handling
	package.  All RPC++ methods return a subclass of an error
	object, which contains a code and a message.  The RPC++
	framework automatically conveys error information from the
	server back to the client and loads the data into the client's
	error handler.  The application writer need only check the code
	and invoke the display routine.

	3. Flexible program number assignment.  The application writer
	specifies the name of an environment variable that can be set
	to override the default program number.

	4. Easy definition of callbacks.  The RPC++ library contains
	methods for acquiring transient numbers.  To register a
	callback, the user need only use a manifest constant in place
	of the program number and then initialize the program.

This is a quick overview of RPC++.  It has been very successful here.
I worked at the socket level for three years, and I would not hesitate
to take the time to re-implement RPC++ before working at the socket
level again.


Availability:

This is a research institute.  We do not create products.  We also
cannot give things away.  We have licensed software in the past and
have discussed licensing RPC++ to a couple of companies.  In any
licensing agreement, we would want to recover our costs for licensing
and distribution as well as some of the development costs.  We also
have research partnership plans for those who want to fund our research
in return for access to the ideas, etc.  I do not handle the business
end, so I do not know how much a reasonable agreement would cost.  I am
also in the middle of writing a grant proposal, so I am reluctant to
encourage people to send me mail for more information.  But, if there
is a reasonable chance that your organization can make a fair licensing
or funding agreement, I would be happy to bring the institute's
director into the discussion.

Cheers!  --Jim