Re: [Boost-users] [boost::asio]Question about how to properly make several async requests (reads and writes)

Subject: Re: [Boost-users] [boost::asio]Question about how to properly make several async requests (reads and writes)
From: Rutger ter Borg (rutger_at_[hidden])
Date: 2009-09-04 12:45:29

Matheus Araújo Aguiar wrote:

> Dear list,
> 
> I have learned that one cannot make several async write requests, one
> after another, without waiting for the completion of each request,
> otherwise the bytes get merged and the messages will not make sense at the
> receiving side. I am correct assuming that, right?
> My doubt is if the same happens to async read requests. Does one have to
> wait a read request completes before issuing another? Will the bytes get
> merged too, if one does not wait before making another read request?
> 
> Assuming things happen that way, one async request waiting for the
> completion of another earlier request, then one have serial I/O processing
> and if one wants to have things done in parallel, the simplest way would
> be having other(s) thread(s) reading and writting in the same I/O object.
> Is this correct?
> 
> I hope I have made my doubts clear enough, and if it is not clear please
> say it and i will try to be more objective.
> 
> Regards,

Several read/write requests may not make sense because each read/write 
request may be split up in several read_some/write_some requests. Suppose 
you have a larger message A, and a smaller B, and you issue AB, it may be 
transmitted as A1BA2.

You can issue a read and write request before completion of either to 
achieve full duplex communication with just one thread.

Kind regards,

Rutger ter Borg