Re: [Boost-users] New library for RPC-calls using only boost and C++0x

Subject: Re: [Boost-users] New library for RPC-calls using only boost and C++0x
From: Siegfried Kettlitz (siegfried.kettlitz_at_[hidden])
Date: 2009-06-12 11:25:26

@Roman:
I took a quick look at Jarl Lindrud RCF library. It is in some ways
similar but very different in others. The separate client/server
concept differs a lot from the node-concept used in my library. I
didn't quite understand how objects are handled and addressed in RCF
and if it is possible to have two objects of the same type at one
server and addressable by one client.

Marshalling of in/out variables is one part that is missing in my
library. This would be nice for synchronous calls, but could be very
bad for asynchronous calls.

Using macros to register the functions may be nice for users, but it
should not be necessary (which it is for RCF). It provides a proxy
class for making the calls to remote functions, which is nice to have.

One thing i don't like about RCF is, that it needs the program-wide
initialization of the framework in contrast to instancing nodes in my
library. Another thing is the dependence on TCP connections, sometimes
you need to connect clients where the IP is not available (e.g. via
RS232 over optical coupling).

After all RCF looks like a more specialized approach compared to my
library, but RCF looks like it's easier to get started with than my
library so far - something that needs improvement.

Do you have experience with using RCF?

@Jens Weller
The type of serialization is selected by a typedef:
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
typedef boost::archive::text_iarchive iarchive_t;
typedef boost::archive::text_oarchive oarchive_t;

The archive types occur in the messages for packing/unpacking and some
internal functions for function call forwarding. The archive type can
easily be replaced by an archive type with a similar interface. The
message header encoding also can be easily changed and merged with the
information encoded in the archive.

Another encoding would be useful to make calls from/to other
programming languages, but my library is not designed to be able to
communicate with programs, which are not written in c++ and doesn't
contain a portable interface definition. One main problem is, that the
communication between nodes in my library is not compatible with
anything but itself and so far there is no way of "just calling" to
some host outside, that isn't a node. Using proxy-classes and a
proxy-node to call from/to other systems would be possible and
generating them from IDL should also be possible.

The question is, for what reason would you want to use another
encoding for the messages between the nodes?

@Damien Hocking
Microsoft not supporting variadic templates is a problem, if you
depend on VS. I was under the impression, that Microsoft was ahead of
its time and already had all major things in place for C++0x. Thanks
for correcting this view.