siginfo(3): Document SI_LWP signal code.

Describe SI_LWP as being generated by pthread_kill() because thr_kill() is
a private undocumented function.

MFC after:	1 week

1 files changed, 14 insertions, 2 deletions

diff --git a/share/man/man3/siginfo.3 b/share/man/man3/siginfo.3
index f711653..cbbb33b 100644
--- a/share/man/man3/siginfo.3
+++ b/share/man/man3/siginfo.3
@@ -197,6 +197,9 @@ signal generated by completion of an asynchronous I/O request
 signal generated by arrival of a message on an empty message queue
 .It Ta Dv SI_KERNEL Ta
 signal generated by miscellaneous parts of the kernel
+.It Ta Dv SI_LWP Ta
+signal sent by
+.Xr pthread_kill 3
 .El
 .Pp
 In addition, the following signal-specific information is available:
@@ -273,6 +276,10 @@ the value passed to
 system call
 .It Ta Va si_mqd Ta
 the ID of the message queue which generated the signal
+.It Dv SI_LWP Ta Va si_pid Ta
+the process ID that sent the signal
+.It Ta Va si_uid Ta
+real user ID of the process that sent the signal
 .El
 .Sh NOTES
 Currently, the kernel never generates the
@@ -284,9 +291,10 @@ signal is queued when a process changed its status or exited.
 Realtime Extensions like aio, timer, and message queue also queue
 signals.
 Signals with code
-.Dv SI_USER
-or
+.Dv SI_USER ,
 .Dv SI_KERNEL
+or
+.Dv SI_LWP
 are only queued if there are sufficient resources;
 otherwise,
 .Dv SI_NOINFO
@@ -321,6 +329,10 @@ and
 .Dv SI_KERNEL
 can be generated as of
 .Fx 8.1 .
+The code
+.Dv SI_LWP
+can be generated as of
+.Fx 9.0 .
 .Sh AUTHORS
 This manual page was written by
 .An "David Xu" Aq davidxu@FreeBSD.org .