[src/trunk]: src/share/man/man9 Document interaction of SYSCTL_SETUP function...

[pgoyette <pgoyette%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3707ccb7d84e
branches:  trunk
changeset: 458712:3707ccb7d84e
user:      pgoyette <pgoyette%NetBSD.org@localhost>
date:      Wed Aug 07 13:22:00 2019 +0000

description:
Document interaction of SYSCTL_SETUP functions and the module loader.

diffstat:

 share/man/man9/sysctl.9 |  14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)

diffs (45 lines):

diff -r 4b331b99cc54 -r 3707ccb7d84e share/man/man9/sysctl.9
--- a/share/man/man9/sysctl.9   Wed Aug 07 12:36:36 2019 +0000
+++ b/share/man/man9/sysctl.9   Wed Aug 07 13:22:00 2019 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: sysctl.9,v 1.20 2017/07/03 21:28:48 wiz Exp $
+.\"    $NetBSD: sysctl.9,v 1.21 2019/08/07 13:22:00 pgoyette Exp $
 .\"
 .\" Copyright (c) 2004 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -27,7 +27,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd December 4, 2011
+.Dd August 7, 2019
 .Dt SYSCTL 9
 .Os
 .Sh NAME
@@ -547,7 +547,7 @@
 .Fa oldlenp
 to zero, and returns success.
 .Sh SETUP FUNCTIONS
-Though nodes can be added to the SYSCTL tree at any time, in order to
+Although nodes can be added to the SYSCTL tree at any time, in order to
 add nodes during the kernel bootstrap phase, a proper
 .Dq setup
 function must be used.
@@ -561,9 +561,17 @@
 kernel configuration in
 .Xr options 4 .
 .Pc
+.Pp
 The address of the function is added to a list of functions that
 .Fn sysctl_init
 traverses during initialization.
+For loadable kernel modules (see
+.Xr modules 9 ) ,
+the list of functions is called from the module loader after the module's
+initialization routine.
+Any sysctl nodes created for the loadable module are removed using
+.Fn sysctl_teardown
+before calling the module's termination code.
 .Pp
 Setup functions do not have to add nodes to the main tree, but can set
 up their own trees for emulation or other purposes.