svn commit: r253656 - head/lib/libc/sys

John Baldwin jhb at
Thu Jul 25 19:34:24 UTC 2013

Author: jhb
Date: Thu Jul 25 19:34:24 2013
New Revision: 253656

  Enhance the description of NOTE_TRACK:
  - NOTE_TRACK has never triggered a NOTE_TRACK event from the parent pid.
    If NOTE_FORK is set, the listener will get a NOTE_FORK event from
    the parent pid, but not a separate NOTE_TRACK event.
  - Explicitly note that the event added to monitor the child process
    preserves the fflags from the original event.
  - Move the description of NOTE_TRACKERR under NOTE_TRACK as it is not a
    bit for the user to set (which is what this list pupports to be).
    Also, explicitly note that if an error occurs, the NOTE_CHILD event
    will not be generated.
  MFC after:	1 week


Modified: head/lib/libc/sys/kqueue.2
--- head/lib/libc/sys/kqueue.2	Thu Jul 25 19:10:23 2013	(r253655)
+++ head/lib/libc/sys/kqueue.2	Thu Jul 25 19:34:24 2013	(r253656)
@@ -388,20 +388,25 @@ The process has called
 The process has executed a new process via
 .Xr execve 2
-or similar call.
+or a similar call.
 Follow a process across
 .Fn fork
-The parent process will return with NOTE_TRACK set in the
+The parent process registers a new kevent to monitor the child process
+using the same
 .Va fflags
-field, while the child process will return with NOTE_CHILD set in
+as the original event.
+The child process will signal an event with NOTE_CHILD set in
 .Va fflags
 and the parent PID in
 .Va data .
-This flag is returned if the system was unable to attach an event to
-the child process, usually due to resource limitations.
+If the parent process fails to register a new kevent
+.Pq usually due to resource limitations ,
+it will signal an event with NOTE_TRACKERR set in
+.Va fflags ,
+and the child process will not signal a NOTE_CHILD event.
 On return,

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