The EvChild class
(PECL ev >= 0.2.0)
watchers trigger when the process receives a
in response to some child status changes (most typically when a child dies
or exits). It is permissible to install an
watcher after the child has been forked(which implies it might have
already exited), as long as the event loop isn't entered(or is continued
from a watcher), i.e. forking and then immediately registering a watcher
for the child is fine, but forking and registering a watcher a few event
loop iterations later or in the next callback invocation is not.
It is allowed to register EvChild watchers in the default loop only.
$value= ?): bool
Readonly . The process ID this watcher watches out for, or
0, meaning any process ID.
Readonly .The process ID that detected a status change.
Readonly . The process exit status caused by rpid .