From: Eric Woodruff (Eric.Woodruff_at_[hidden])
Date: 2002-08-05 12:49:17
Personally, I don't think advanced_thread should compose a boost::thread or derive from it. boost::thread is fairly impotent. If the advanced_thread was named asyncronous_function_adapter, boost::thread would be depreciated, as I said earlier. (Of course, for the platform neutrality, asyncronous_function_adapter would have to dervive from a protected private base class where the platform-specific code would reside.)
However, removing the non-templated (publically accessible) base type would probably introduce complexity in the thread pool (which would again need to be renamed if the thread was thrown out). I suggest instead putting boost::thread in a sub namespace and frowning at its use.
----- Original Message -----
From: Moore, Dave
Newsgroups: gmane.comp.lib.boost.devel
Sent: Monday, 2002:August:05 12:59 PM
Subject: RE: Re: Threads & Exceptions
> My complaints on the ifdefs were on the underside of the thread. C++ alone
provides plenty of
> mechanisms for mapping the common interface to different platforms, with
typesafety (instead of
> the reinterpret_casts<>!)--again, the topic of a different discussion, at
which point it would be
> easier just to submit a replacement as example.
Fair enough, but it's a hard problem to solve w/o resorting to (1)
#including os-specific files like <windows.h> in the interface which wreak
havoc on namespaces, macros, etc., or (2) having a complete shadow set of
dynamically allocated Pimpl classes. It's always interesting to see
alternative approaches, though.
> There is no reason to make users of thread handle their own exceptions
because there is only one
> mechanism to do it, and every user will have to repeat this code in their
implementation.
> in thread processes have always been ambiguous to me, it seems that no
framework out there
> supportws them properly and just expects them to be caught and sometimes
ignored.
> If you'll take note of the advanced_thread usage, it not provides a
generic way to run any
> boost::function asynchronously, get its return value and deal with
exceptions it may throw--a
>complete solution and something currently not yet available. Of course one
could take the
>perspective that advanced_thread is really an asynchronous function
adapter, but that deprecates the >need to support what is currently offered
by boost::thread--which is why I suggested a possible
>replacement.
I agree with your statements about reuse and flexibitly for asynchronous
function calls and flexibility in handling exceptions. I'm just not sure
that an inheritance from (or replacement of) boost:thread is the best
solution.
Consider an alternative: a thread_pool object which can enqueue
boost::function calls and distribute them to a managed pool of threads ready
to execute them. boost::function gives you the hook to implement -any-
scenario of argument passing, return value capture, and exception handling
you wish. This is a problem (IMHO) that suggests a solution via composition
of two existing classes, not inheritance.
See:
http://groups.yahoo.com/group/boost/files/thread_pool.zip
For a draft of a solution which may (hopefully) find its way into
Boost.Threads.
Regards,
Dave
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