From: Karel Zak <kzak@redhat.com>
Date: Tue, 15 Jan 2013 10:14:03 +0000 (+0100)
Subject: kill: add note about threads to the man page
X-Git-Tag: v2.23-rc1~352
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=741587f3e97ee8b610c54860ccc40b351aef14ee;p=thirdparty%2Futil-linux.git

kill: add note about threads to the man page

Addresses: http://bugzilla.redhat.com/show_bug.cgi?id=846790
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/misc-utils/kill.1 b/misc-utils/kill.1
index 09d30e9cd0..404fb724ed 100644
--- a/misc-utils/kill.1
+++ b/misc-utils/kill.1
@@ -97,6 +97,26 @@ signal.  If the receiving process has installed a handler for this signal using
 the SA_SIGINFO flag to
 .BR sigaction (2),
 then it can obtain this data via the si_value field of the siginfo_t structure.
+.SH NOTES
+It's not possible to send a signal to explicitly selected thread in a
+multithreaded process by
+.BR kill (2)
+syscall. If
+.BR kill(2)
+is used to send a signal to a thread group,  then
+kernel selects arbitrary member of the thread group that has not blocked
+the signal. For more details see
+.BR clone (2)
+CLONE_THREAD description.
+
+The command
+.BR kill (1)
+as well as syscall
+.BR kill (2)
+accepts TID (thread ID, see
+.BR gettid (2))
+as argument. In this case the kill behavior is not changed and the signal is
+also delivered to the thread group rather than to the specified thread.
 .SH "SEE ALSO"
 .BR bash (1),
 .BR tcsh (1),