bug#8855: dbus error at startup

[Paul Eggert]

On 10/29/2012 10:06 AM, Eli Zaretskii wrote:

> Since we are now asking about a single
> process at a time, I don't see why we need a loop inside a loop.

Good point, and this is a performance regression, since the
old code was O(N) and the new O(N**2).  I have fixed that
in a revised proposal (attached).  While fixing this I
found another regression, as already successfully-
waited-for processes were being waited-for again.  This is also
fixed in the revised proposal.

> Btw, what about Posix platforms that don't have WNOHANG defined,

There aren't any anymore.  Posix has required WNOHANG since
Posix.1-1988 and everybody has it implemented by now.
I've added a comment to that effect.  (I also added a comment
along the line that cyd suggested.)

> (The cpp directives don't match.)

Thanks, fixed in the attached proposal.

> I guess time is ripe for refactoring that code into an emulation
> of 'waitpid'.

Yes, that'd be nice.  The attached proposal puts that into a FIXME
comment.

> We use record_child_status_change in another place as well: in
> sysdep.c:wait_for_termination_1.  Will the change in the former still
> work correctly in the latter (and its callers)?

Yes, it should.  One uses -1 as the pid as a special indicator; the
other doesn't, and the implementation treats -1 specially.

Thanks for the review.

g_spawn_sync.txt
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