Re: [boost] [Review] Shmem Library

From: Kevin Heifner (heifner_k_at_[hidden])
Date: 2006-02-09 14:11:25

Pavel Antokolsky aka Zigmar wrote:
>> - What is your evaluation of the design?
> In general - I liked it. It looks a bit complicated in some places,
> but I guess this is tradeoff played for its power. I've made several
> tests and found that library is easy enough to use, yet powerful
> enough to do what most people need for IPC communications.
> 
> One minor thing, I didn't particularly liked about design is that
> several method (for example shared_message_queue::receive) return
> values into variables passed by non-const reference. I don't like this
> approach - the resulting code is obscure because you can't see from
> that code, that variable is modified. I think of the the following
> approaches might result a better client code:
> 1) Return multiple values (i.e. by using std::pair, boost::tuple)
> 2) Modify parameters, but instead of passing by non-const reference -
> pass them by pointer. When pointer passed it immediately indicates
> that variable might be modified as opposite to non-const reference,
> which is a rare beast nowadays. If you think of  foo(someVar) via
> foo(&someVar), the second hints about possibility of modifying
> someVar, while first one doesn't.

I have not had time to look into shmem yet, so my comment is only 
to the above text without looking at the code.

1) This is not always a good idea because of the cost of copying 
a returned object.  Also when using templated functions the 
compiler can deduce the type from the argument instead of having 
to specify it explicitly.

2) No, No, No.  I strive for pointer free code.  A method that 
advertises a non-const reference tells you that it will modify 
the object.  A const reference indicates that it will not.  A 
function that takes a pointer tells me nothing.

KevinH
-- 
Kevin Heifner  heifner @ ociweb.com  http://heifner.blogspot.com
           Object Computing, Inc. (OCI) www.ociweb.com