Re: [boost] asio review extended till Dec 30th

From: Jody Hagins (jody-boost-011304_at_[hidden])
Date: 2005-12-29 17:51:34

On Fri, 30 Dec 2005 08:54:01 +1100 (EST)
Christopher Kohlhoff <chris_at_[hidden]> wrote:

> > However, of some concern is the fact that you call
> > epoll_wait() from multiple threads using the same epoll fd.
> 
> Actually epoll_wait is only called from one thread at a time.
> This coordination is managed by the task_demuxer_service.

So, that class calls the impl run() method, and it makes sure it is only
entered once?  What if a handler calls demuxer.run()?

> Maybe have a look at the chat or serialization examples, since
> the message format used in these programs is a fixed length
> header followed by a body.

OK.  Thanks.

You have an interface to read N bytes.  What about an interface to read
until a message terminator is found?

> > async_read() does not provide the buffer to the handler.  It
> > seems the only way to use it is with a function object that
> > contains the buffer.  Is that a correct understanding, or do I
> > just need to go back to sleep?
> 
> Binding it into the function object is one way. But often this
> binding is indirect, in the sense that you bind a this pointer
> and the buffer is a data member of the class.

But, what if I want to use a free function as my handler?  I can't
because the data is not provided.  Also, now I have coupled the start of
the read with its handling.

What about my earlier question of "keep reading and notifying me until
EOF?"  That's not how I worded it, but let's say I have an application
and I want the same handler called for all IO until the socket is
closed.  Right now, I *think* I have to keep creating async objects and
calls each time I process some data.  This seems a bit wasteful.  I'd
like to "reuse" the same handler without binding again, or I'd like to
just tell the framework...  Keep calling this handler for every piece of
data.