Re: [boost] [gsoc] Boost.Process done

Subject: Re: [boost] [gsoc] Boost.Process done
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-09-13 14:15:13

Jeremy Maitin-Shepard wrote:
> On 09/13/2010 04:41 AM, Stewart, Robert wrote:
>
> > Is not signal handling a process-specific behavior?  It may be
> > POSIX-specific, but it seems reasonable that Boost.Process
> > provide signal handling support.  Then, Boost.Process can require
> > that all code in a process using that library must coordinate
> > with its signal handling.
>
> I would not say that general signal handling falls within the
> domain of Boost.Process, but it may make sense for
> Boost.Process to depend on a not-yet-existent Boost POSIX
> Signal Handling library.

I have no problem with that.

> Note, however, that coordination solely at the level of signals
> is not sufficient, at least if the code is to scale to many
> child processes. Rather, specific coordination with respect to
> SIGCHLD and waitpid is needed.

Hmmm.  As I see it, Boost.Process would know which child
processes it created and would only call waitpid() on those.  No
code outside the library would need to call waitpid() on those.
All that's needed is for Boost.Process' SIGCHLD handler to be
invoked and, if the other code needs a SIGCHLD handler, that it
be invoked by the same mechanism, to ensure correct chaining, and
that the other code never calls waitpid() for child processes
that Boost.Process creates.

Is that what you meant by "specific coordination?"  That's not
coordination so much as clear delineation of responsibilities and
behaviors, but it would mean we were just talking past one
another.  If you meant something else, please clarify.

_____
Rob Stewart                           robert.stewart_at_[hidden]
Software Engineer, Core Software      using std::disclaimer;
Susquehanna International Group, LLP  http://www.sig.com

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