Re: [boost] [interprocess][process] Synchronizing libraries and efforts (+ bugs)

From: Boris (boriss_at_[hidden])
Date: 2008-08-31 18:30:10

On Sun, 31 Aug 2008 23:20:10 +0200, Ion Gaztañaga <igaztanaga_at_[hidden]>  
wrote:

> [...]I understand async I/O should be tied with ASIO. I think  
> Boost.Iostreams

To give you an idea how asynchronous I/O with Boost.Process and Boost.Asio  
currently looks like:

boost::process::child child; // somehow launched
#if defined(_WIN32)
   boost::asio::windows::stream_handle out(io_service,  
child.get_stdin().handle().release());
   boost::asio::windows::stream_handle in(io_service,  
child.get_stdout().handle().release());
#else
   boost::asio::posix::stream_descriptor out(io_service,  
child.get_stdin().handle().release());
   boost::asio::posix::stream_descriptor in(io_service,  
child.get_stdout().handle().release());
#endif
in.async_read_some(...);

> [...]I can wait ;-) Since you are working hard on the library, I think  
> it's better to wait until you consider the library mature enough. Feel  
> free to contact me if you have any question.

OK, I'll tell you once I'm done (as I said I expect until mid September).  
The code is nearly done. But with all the changes which I had to merge I  
definitely need to update the documentation and samples.

By the way, I would be very interested in a communication channel between  
a parent and a child process based on Boost.Interprocess. I need  
asynchronous I/O though. Before I picked up Boost.Process I had created a  
Boost.Asio extension boost::asio::shared_memory which can be used like  
boost::asio::socket. The only (but big :) problem I haven't solved yet is  
how to handle more than one communication channel. As read/write  
operations in Boost.Interprocess need to be synchronized the calls might  
block. A parent process with many children will then have to use at least  
one thread per child. What would be required is a demultiplexer which  
would work like select() for file descriptors. Then I think asynchronous  
I/O could be done with Boost.Interprocess. The question is though what  
would that demultiplexer look like? You are not working on supporting  
asynchronous I/O in Boost.Interprocess? ;)

Boris

> [...]