On Mon, Aug 12, 2013 at 8:58 AM, Niall Douglas
I would URGE you to make this exclusively a Boost.ASIO implementation. That is the correct fit for pipes, moreover Boost.ASIO does almost all the heavy lifting for you, especially on Windows where I suspect a Win32 named pipe implementation will take about eight lines of new code as the ASIO IOCP backend "just works". There is an IOCP example in the ASIO documentation which I believe even implements those eight lines for you :)
That solves your data buffers problem, because ASIO already implements scatter/gather buffer i/o for you. ASIO also already integrates with STL iostreams and Boost.iostreams for you.
Regarding some of the other comments on this list regarding your proposal:
1. Any async op can be made synchronous by waiting on it. Therefore an ASIO based named pipe is just as easy to use synchronously as asynchronously.
2. ASIO is the proposed foundation for the future C++ standard networking library, so adding named pipes there is exactly the right place to enter any future C++ standard.
I like this idea. I wasn't sure it was appropriate though and frankly, from having poked through the source a bit, ASIO is a bit intimidating in the way it's structured. But I'm sure that's mostly a lack of familiarity with it and only vaguely understanding the core principles which can surely be remedied by some study of the documentation.
3. There seemed to be some confusion regarding named pipes on POSIX. The only difference between Windows and POSIX named pipes is that the former use the NT kernel namespace, within which the filing systems are mount points, whereas the latter use the filing system namespace directly. In my own code, I use a magic directory in /tmp as the namespace for all my named pipes in the system in an attempt to replicate a similar behavior to Windows, but there are many other ways of doing the same thing.
Hmmm, I see what you're saying and I agree with it, but I'm also not sure that it's strictly true that this is the "only" difference. Also, to clarify when you say POSIX named pipes, you are talking about the mkfifo call, correct? And is there a reason why the mkfifo call is more desirable to use than UNIX domain sockets?
Anonymous pipes are also slightly different - on POSIX they really are anonymous, whereas on Windows they get given a random hex id for their name. There is absolutely no reason why on POSIX you can't also use a random hex id for their name, and indeed that is also exactly what my own code does.
BTW are you aware of the +24 buffer size bug in Windows' pipe implementation? It's a known bug since very early NT days :)
I was not! Thanks for the tip :) Also, FYI, I'm doing this project as an independent study through my CS program. I'm getting close to the end of the quarter and I need to have something concrete to show for my efforts. Since I've already started down the path of implementing this not inside of Boost.ASIO, for the purposes of my school project I'm going to continue with that. However, I plan to continue working on it after the scholastic bit is finished, and then I would be interested in implementing it as part of ASIO. -- Geoff Nothing is ever easy.