On 22/03/2018 22:56, Thomas Quarendon wrote:
Yes, sorry. Yes, you can create pipes in Windows, but asio doesn't support Windows anonymous pipes or concole handles, as they don't support completion ports. But yes, you can create a named port with a unique name (which is what CreatePipe does).
Anonymous pipes created with CreatePipe don't support overlapped I/O, true; but as you said yourself they're just named pipes with a unique name, and CreateNamedPipe *can* support overlapped I/O, so you can make up your own name and use them with a windows::stream_handle to do async reads and writes. It's a little more fiddly but you can also compose your own I/O objects and operations around other APIs, presumably such as TransactNamedPipe. I have some code that turns a shared memory block (with events) into a simple one-slot interprocess ASIO-compatible async mailbox, for example; the key trick was to use windows::object_handle::async_wait to "wait" for something to happen and then read the data synchronously in the wait completion handler (because at that point it is guaranteed to complete without blocking).
Using async initially, then sync to read the "message" works well, it's a nice design, if only I could put a timeout on the synchronous reads.
You can use a deadline_timer and cancel the synchronous read if it trips. It's a bit fugly though and is subject to races. It's much nicer to use async.