On Fri, 26 Mar 2010 03:58:57 +0100, Moncef Mechri <moncef.mechri@gmail.com> wrote:
[...]Yeah :). What do you think about the idea to set up an handler which calls wait() when a SIGCHLD signal is received ? Otherwise, what's your vision of this asynchronous wait() ?
From a user's point of view an asynchronous wait() ideally behaves like any other asynchronous operation supported by Boost.Asio. How the implementation looks like depends then on the platform (on POSIX systems I agree we could and maybe have to catch SIGCHLD).
[...]5) Right now, boost::process::wait_children() returns the first exit
code
which is not equal to EXIT_SUCCESS, and if there are more than one process which finished abnormally, return values of those child processes are ignored. I think we could improve that by returning for example a vector<boost::process::status> instead of just one boost::process::status. Doing that, we can retrieve all the status codes. It might be useful to define a way to toggle on/off
No comment except that creating and managing pipelines is indeed another topic we have to think about.
This means that you're ok with this proposition ?
Yes, no problem (mainly because I'm more concerned about overall design decisions for now :-).
6) Actually in Boost.Process, if the developer wants to be able to do
asynchronous operations on Windows he has to define the BOOST_PROCESS_WINDOWS_USE_NAMED_PIPE macro. By doing so, it makes Boost.Process on Windows create named pipe for all streams even if asynchronous operations are not used in all of them.
I agree it must be changed (adding the macro was a quick fix as asynchronous I/O didn't work at all on Windows before).
I'm going to thing about a concrete proposition to solve this issue
The problem here is that we need an I/O object which needs to be bound to an I/O service object (not sure how familiar you are with Boost.Asio?). Now what's the I/O object in Boost.Process? Shall we think of a process as an I/O object? Can we expect developers to prefer using asynchronous I/O just as they do with sockets for example? If we don't want to force developers to create an I/O service object whenever they work with Boost.Process we need to find another mechanism to turn a process object into an I/O object later (after it has been constructed). This again is something which hasn't been done yet in any Boost library (all other objects support asynchronous I/O right after construction). I think it all comes down whether we want to treat a process like any other I/O object. While noone complains about creating I/O service objects when you use sockets I'm not sure about processes? Developers might be surprised if Boost.Process is coupled with Boost.Asio? Boris