+The information is copied into the buffer specified by \fIoldp\fP.
+The size of the buffer is given by the location specified by \fIoldlenp\fP
+before the call,
+and that location is filled in with the amount of data copied after
+a successful call.
+If the amount of data available is greater
+than the size of the buffer supplied,
+the call supplies as much data as fits in the buffer provided
+and returns an error.
+.PP
+To set a new value, \fInewp\fP
+is set to point to a buffer of length \fInewlen\fP
+from which the requested value is to be taken.
+If a new value is not to be set, \fInewp\fP
+should be set to NULL and \fInewlen\fP set to 0.
+.PP
+The top level names (those used in the first element of the \fIname\fP array)
+are defined with a CTL_ prefix in \fI<sys/sysctl.h>\fP,
+and are as follows.
+The next and subsequent levels down are found
+in the include files listed here:
+.DS
+.TS
+l l l.
+Name Next Level Names Description
+_
+CTL\_DEBUG sys/sysctl.h Debugging
+CTL\_FS sys/sysctl.h Filesystem
+CTL\_HW sys/sysctl.h Generic CPU, I/O
+CTL\_KERN sys/sysctl.h High kernel limits
+CTL\_MACHDEP sys/sysctl.h Machine dependent
+CTL\_NET sys/socket.h Networking
+CTL\_USER sys/sysctl.h User-level
+CTL\_VM vm/vm_param.h Virtual memory
+.TE
+.DE
+.Sh 3 "Bootstrap operations
+.LP
+The call: