sysctl(3)
- NetBSD Manual Pages
SYSCTL(3) NetBSD Programmer's Manual SYSCTL(3)
NAME
sysctl - get or set system information
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/param.h>
#include <sys/sysctl.h>
int
sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
size_t newlen);
DESCRIPTION
The sysctl function retrieves system information and allows processes
with appropriate privileges to set system information. The information
available from sysctl consists of integers, strings, and tables. Infor-
mation may be retrieved and set from the command interface using the
sysctl(8) utility.
Unless explicitly noted below, sysctl returns a consistent snapshot of
the data requested. Consistency is obtained by locking the destination
buffer into memory so that the data may be copied out without blocking.
Calls to sysctl are serialized to avoid deadlock.
The state is described using a ``Management Information Base'' (MIB)
style name, listed in name, which is a namelen length array of integers.
The information is copied into the buffer specified by oldp. The size of
the buffer is given by the location specified by oldlenp before the call,
and that location gives 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 with the error code ENOMEM. If the old value is not
desired, oldp and oldlenp should be set to NULL.
The size of the available data can be determined by calling sysctl with a
NULL parameter for oldp. The size of the available data will be returned
in the location pointed to by oldlenp. For some operations, the amount
of space may change often. For these operations, the system attempts to
round up so that the returned size is large enough for a call to return
the data shortly thereafter.
To set a new value, newp is set to point to a buffer of length newlen
from which the requested value is to be taken. If a new value is not to
be set, newp should be set to NULL and newlen set to 0.
The top level names are defined with a CTL_ prefix in <sys/sysctl.h>, and
are as follows. The next and subsequent levels down are found in the in-
clude files listed here, and described in separate sections below.
Name Next level names Description
CTL_DEBUG sys/sysctl.h Debugging
CTL_VFS sys/mount.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
For example, the following retrieves the maximum number of processes al-
lowed in the system:
int mib[2], maxproc;
size_t len;
mib[0] = CTL_KERN;
mib[1] = KERN_MAXPROC;
len = sizeof(maxproc);
sysctl(mib, 2, &maxproc, &len, NULL, 0);
To retrieve the standard search path for the system utilities:
int mib[2];
size_t len;
char *p;
mib[0] = CTL_USER;
mib[1] = USER_CS_PATH;
sysctl(mib, 2, NULL, &len, NULL, 0);
p = malloc(len);
sysctl(mib, 2, p, &len, NULL, 0);
CTL_DEBUG
The debugging variables vary from system to system. A debugging variable
may be added or deleted without need to recompile sysctl to know about
it. Each time it runs, sysctl gets the list of debugging variables from
the kernel and displays their current values. The system defines twenty
(struct ctldebug) variables named debug0 through debug19. They are de-
clared as separate variables so that they can be individually initialized
at the location of their associated variable. The loader prevents multi-
ple use of the same variable by issuing errors if a variable is initial-
ized in more than one place. For example, to export the variable
dospecialcheck as a debugging variable, the following declaration would
be used:
int dospecialcheck = 1;
struct ctldebug debug5 = { "dospecialcheck", &dospecialcheck };
CTL_VFS
A distinguished second level name, VFS_GENERIC, is used to get general
information about all filesystems. One of its third level identifiers is
VFS_MAXTYPENUM that gives the highest valid filesystem type number. Its
other third level identifier is VFS_CONF that returns configuration in-
formation about the filesystem type given as a fourth level identifier
(see getvfsbyname(3) as an example of its use). The remaining second
level identifiers are the filesystem type number returned by a statfs(2)
call or from VFS_CONF. The third level identifiers available for each
filesystem are given in the header file that defines the mount argument
structure for that filesystem.
CTL_HW
The string and integer information available for the CTL_HW level is de-
tailed below. The changeable column shows whether a process with appro-
priate privilege may change the value.
Second level name Type Changeable
HW_MACHINE string no
HW_MODEL string no
HW_NCPU integer no
HW_BYTEORDER integer no
HW_PHYSMEM integer no
HW_USERMEM integer no
HW_PAGESIZE integer no
HW_MACHINE_ARCH string no
HW_MACHINE
The machine class.
HW_MODEL
The machine model
HW_NCPU
The number of cpus.
HW_BYTEORDER
The byteorder (4,321, or 1,234).
HW_PHYSMEM
The bytes of physical memory.
HW_USERMEM
The bytes of non-kernel memory.
HW_PAGESIZE
The software page size.
HW_MACHINE_ARCH
The machine cpu class.
CTL_KERN
The string and integer information available for the CTL_KERN level is
detailed below. The changeable column shows whether a process with ap-
propriate privilege may change the value. The types of data currently
available are process information, system vnodes, the open file entries,
routing table entries, virtual memory statistics, load average history,
and clock rate information.
Second level name Type Changeable
KERN_ARGMAX integer no
KERN_AUTONICETIME integer yes
KERN_AUTONICEVAL integer yes
KERN_BOOTTIME struct timeval no
KERN_CHOWN_RESTRICTED integer no
KERN_CLOCKRATE struct clockinfo no
KERN_DOMAINNAME string yes
KERN_FILE struct file no
KERN_FSYNC integer no
KERN_HOSTID integer yes
KERN_HOSTNAME string yes
KERN_IOV_MAX integer no
KERN_JOB_CONTROL integer no
KERN_LINK_MAX integer no
KERN_MAXFILES integer yes
KERN_MAXPARTITIONS integer no
KERN_MAXPROC integer yes
KERN_MAXVNODES integer yes
KERN_MAX_CANON integer no
KERN_MAX_INPUT integer no
KERN_MSGBUFSIZE integer no
KERN_NAME_MAX integer no
KERN_NGROUPS integer no
KERN_NO_TRUNC integer no
KERN_OSRELEASE string no
KERN_OSREV integer no
KERN_OSTYPE string no
KERN_PATH_MAX integer no
KERN_PIPE_BUF integer no
KERN_POSIX1 integer no
KERN_PROC struct proc no
KERN_PROF node not applicable
KERN_RAWPARTITION integer no
KERN_SAVED_IDS integer no
KERN_SECURELVL integer raise only
KERN_SHORTCORENAME integer yes
KERN_SYNCHRONIZED_IO integer no
KERN_SYSVMSG integer no
KERN_SYSVSEM integer no
KERN_SYSVSHM integer no
KERN_VDISABLE integer no
KERN_VERSION string no
KERN_VNODE struct vnode no
KERN_ARGMAX
The maximum bytes of argument to execve(2).
KERN_AUTONICETIME
The number of seconds of cpu-time a non-root process may accumu-
late before having its priority lowered from the default to the
value of KERN_AUTONICEVAL. If set to 0, automatic lowering of
priority is not performed, and if set to -1 all non-root process-
es are immediately lowered.
KERN_AUTONICEVAL
The priority assigned for automatically niced processes.
KERN_BOOTTIME
A struct timeval structure is returned. This structure contains
the time that the system was booted.
KERN_CHOWN_RESTRICTED
Return 1 if appropriate privileges are required for the chown(2)
system call, otherwise 0.
KERN_CLOCKRATE
A struct clockinfo structure is returned. This structure con-
tains the clock, statistics clock and profiling clock frequen-
cies, the number of micro-seconds per hz tick, and the clock skew
rate.
KERN_DOMAINNAME
Get or set the YP domain name.
KERN_FILE
Return the entire file table. The returned data consists of a
single struct filehead followed by an array of struct file, whose
size depends on the current number of such objects in the system.
KERN_FSYNC
Return 1 if the POSIX 1003.1b File Synchronization Option is
available on this system, otherwise 0.
KERN_HOSTID
Get or set the host id.
KERN_HOSTNAME
Get or set the hostname.
KERN_IOV_MAX
Return the maximum number of iovec structures that a process has
available for use with preadv(2), pwritev(2), readv(2),
recvmsg(2), sendmsg(2) and writev(2).
KERN_JOB_CONTROL
Return 1 if job control is available on this system, otherwise 0.
KERN_LINK_MAX
The maximum file link count.
KERN_MAXFILES
The maximum number of open files that may be open in the system.
KERN_MAXPARTITIONS
The maximum number of partitions allowed per disk.
KERN_MAXPROC
The maximum number of simultaneous processes the system will al-
low.
KERN_MAXVNODES
The maximum number of vnodes available on the system.
KERN_MAX_CANON
The maximum number of bytes in terminal canonical input line.
KERN_MAX_INPUT
The minimum maximum number of bytes for which space is available
in a terminal input queue.
KERN_MSGBUFSIZE
The maximum number of characters that the kernel message buffer
can hold.
KERN_NAME_MAX
The maximum number of bytes in a file name.
KERN_NGROUPS
The maximum number of supplemental groups.
KERN_NO_TRUNC
Return 1 if file names longer than KERN_NAME_MAX are truncated.
KERN_OSRELEASE
The system release string.
KERN_OSREV
The system revision string.
KERN_OSTYPE
The system type string.
KERN_PATH_MAX
The maximum number of bytes in a pathname.
KERN_PIPE_BUF
The maximum number of bytes which will be written atomically to a
pipe.
KERN_POSIX1
The version of ISO/IEC 9945 (POSIX 1003.1) with which the system
attempts to comply.
KERN_PROC
Return the entire process table, or a subset of it. An array of
struct kinfo_proc structures is returned, whose size depends on
the current number of such objects in the system. The third and
fourth level names are as follows:
Third level name Fourth level is:
KERN_PROC_ALL None
KERN_PROC_PID A process ID
KERN_PROC_PGRP A process group
KERN_PROC_TTY A tty device
KERN_PROC_UID A user ID
KERN_PROC_RUID A real user ID
KERN_PROF
Return profiling information about the kernel. If the kernel is
not compiled for profiling, attempts to retrieve any of the
KERN_PROF values will fail with EOPNOTSUPP. The third level
names for the string and integer profiling information is de-
tailed below. The changeable column shows whether a process with
appropriate privilege may change the value.
Third level name Type Changeable
GPROF_STATE integer yes
GPROF_COUNT u_short[] yes
GPROF_FROMS u_short[] yes
GPROF_TOS struct tostruct yes
GPROF_GMONPARAM struct gmonparam no
The variables are as follows:
GPROF_STATE
Returns GMON_PROF_ON or GMON_PROF_OFF to show that pro-
filing is running or stopped.
GPROF_COUNT
Array of statistical program counter counts.
GPROF_FROMS
Array indexed by program counter of call-from points.
GPROF_TOS
Array of struct tostruct describing destination of calls
and their counts.
GPROF_GMONPARAM
Structure giving the sizes of the above arrays.
KERN_RAWPARTITION
The raw partition of a disk (a == 0).
KERN_SAVED_IDS
Returns 1 if saved set-group and saved set-user ID is available.
KERN_SECURELVL
The system security level. This level may be raised by processes
with appropriate privilege. It may only be lowered by process 1.
KERN_SHORTCORENAME
Whether core dumps are named programname.core (default, value 0)
or core (value 1). The default value can be changed to 1 with
the kernel configuration option
options SHORTCORENAME (see options(4), core(5)).
KERN_SYNCHRONIZED_IO
Returns 1 if the POSIX 1003.1b Synchronized I/O Option is avail-
able on this system, otherwise 0.
KERN_SYSVMSG
Returns 1 if System V style message queue functionality is avail-
able on this system, otherwise 0.
KERN_SYSVSEM
Returns 1 if System V style semaphore functionality is available
on this system, otherwise 0.
KERN_SYSVSHM
Returns 1 if System V style share memory functionality is avail-
able on this system, otherwise 0.
KERN_VDISABLE
Returns the terminal character disabling value.
KERN_VERSION
The system version string.
KERN_VNODE
Return the entire vnode table. Note, the vnode table is not nec-
essarily a consistent snapshot of the system. The returned data
consists of an array whose size depends on the current number of
such objects in the system. Each element of the array contains
the kernel address of a vnode struct vnode * followed by the vn-
ode itself struct vnode.
CTL_MACHDEP
The set of variables defined is architecture dependent. Most architec-
tures define at least the following variables.
Second level name Type Changeable
CPU_CONSDEV dev_t no
CTL_NET
The string and integer information available for the CTL_NET level is de-
tailed below. The changeable column shows whether a process with appro-
priate privilege may change the value.
Second level name Type Changeable
PF_ROUTE routing messages no
PF_INET internet values yes
PF_ROUTE
Return the entire routing table or a subset of it. The data is
returned as a sequence of routing messages (see route(4) for the
header file, format and meaning). The length of each message is
contained in the message header.
The third level name is a protocol number, which is currently al-
ways 0. The fourth level name is an address family, which may be
set to 0 to select all address families. The fifth and sixth
level names are as follows:
Fifth level name Sixth level is:
NET_RT_FLAGS rtflags
NET_RT_DUMP None
NET_RT_IFLIST None
PF_INET
Get or set various global information about the internet proto-
cols. The third level name is the protocol. The fourth level
name is the variable name. The currently defined protocols and
names are:
Protocol name Variable name Type Changeable
ip forwarding integer yes
ip redirect integer yes
ip ttl integer yes
ip forwsrcrt integer yes
ip directed-broadcast integer yes
ip allowsrcrt integer yes
ip subnetsarelocal integer yes
ip mtudisc integer yes
ip anonportmin integer yes
ip anonportmax integer yes
ip mtudisctimeout integer yes
icmp maskrepl integer yes
tcp rfc1323 integer yes
tcp sendspace integer yes
tcp recvspace integer yes
tcp mssdflt integer yes
tcp syn_cache_limit integer yes
tcp syn_bucket_limit integer yes
tcp syn_cache_interval integer yes
tcp init_win integer yes
tcp mss_ifmtu integer yes
tcp sack integer yes
tcp win_scale integer yes
tcp timestamps integer yes
tcp compat_42 integer yes
tcp cwm integer yes
tcp cwm_burstsize integer yes
tcp ack_on_push integer yes
tcp keepidle integer yes
tcp keepintvl integer yes
tcp keepcnt integer yes
tcp slowhz integer no
tcp newreno integer yes
udp checksum integer yes
udp sendspace integer yes
udp recvspace integer yes
The variables are as follows:
ip.forwarding
Returns 1 when IP forwarding is enabled for the host,
meaning that the host is acting as a router.
ip.redirect
Returns 1 when ICMP redirects may be sent by the host.
This option is ignored unless the host is routing IP
packets, and should normally be enabled on all systems.
ip.ttl The maximum time-to-live (hop count) value for an IP
packet sourced by the system. This value applies to nor-
mal transport protocols, not to ICMP.
ip.forwsrcrt
Returns 1 when forwarding of source-routed packets is en-
abled for the host. This value may only be changed if
the kernel security level is less than 1.
ip.directed-broadcast
Returns 1 if directed broadcast behavior is enabled for
the host.
ip.allowsrcrt
Returns 1 if the host accepts source routed packets.
ip.subnetsarelocal
Returns 1 if subnets are to be considered local address-
es.
ip.mtudisc
Returns 1 if Path MTU Discovery is enabled.
ip.anonportmin
The lowest port number to use for TCP and UDP ephemeral
port allocation. This cannot be set to less that 1024 or
greater than 65535.
ip.anonportmax
The highest port number to use for TCP and UDP ephemeral
port allocation. This cannot be set to less that 1024 or
greater than 65535, and must be greater than
ip.anonportmin.
ip.mtudisctimeout
Returns the number of seconds in which a route added by
the Path MTU Discovery engine will time out. When the
route times out, the Path MTU Discovery engine will at-
tempt to probe a larger path MTU.
icmp.maskrepl
Returns 1 if ICMP network mask requests are to be an-
swered.
tcp.rfc1323
Returns 1 if RFC1323 extensions to TCP are enabled.
tcp.sendspace
Returns the default TCP send buffer size.
tcp.recvspace
Returns the default TCP receive buffer size.
tcp.mssdflt
Returns the default maximum segment size both advertsized
to the peer and to use when the peer does not advertize a
maximum segment size to us during connection setup. Do
not change this value unless you really know what you are
doing.
tcp.syn_cache_limit
Returns the maximum number of entries allowed in the TCP
compressed state engine.
tcp.syn_bucket_limit
Returns the maximum number of entries allowed per hash
bucket in the TCP compressed state engine.
tcp.syn_cache_interval
Returns the TCP compressed state engine's timer interval.
tcp.init_win
Returns a value indicating the TCP initial congestion
window. If this value is 0, an auto-tuning algorithm de-
signed to use an initial window of approximately 4K bytes
is in use. Otherwise, this value indicates a fixed num-
ber of packets.
tcp.mss_ifmtu
Returns 1 if TCP calculates the outgoing maximum segment
size based on the MTU of the appropriate interface. Oth-
erwise, it is calculated based on the greater of the MTU
of the interface, and the largest (non-loopback) inter-
face MTU on the system.
tcp.sack
Returns a value which determines the level of Selective
Acknowledgement supported by TCP. If 2, we will transmit
and receive SACK options. If 1, we will transmit SACK
options, but ignore any SACK options received. If 0,
SACK is disabled.
tcp.win_scale
If rfc1323 is enabled, a value of 1 indicates RFC1323
window scale options, for increasing the TCP window size,
are enabled.
tcp.timestamps
If rfc1323 is enabled, a value of 1 indicates RFC1323
time stamp options, used for measuring TCP round trip
times, are enabled.
tcp.compat_42
Returns 1 if work-arounds for bugs in the 4.2BSD TCP im-
plementation are enabled. Use of this option is not rec-
ommended, although it may be required in order to commu-
nicate with extremely old TCP implementations.
tcp.cwm
Returns 1 if use of the Hughes/Touch/Heidemann Congestion
Window Monitoring algorithm is enabled. This algorithm
prevents line-rate bursts of packets that could otherwise
occur when data begins flowing on an idle TCP connection.
These line-rate bursts can contribute to network and
router congestion. This can be particularly useful on
World Wide Web servers which support HTTP/1.1, which has
lingering connections.
tcp.cwm_burstsize
Returns the Congestion Window Monitoring allowed burst
size, in terms of packet count.
tcp.ack_on_push
Returns 1 if TCP is to immediately transmit an ACK upon
reception of a packet with PUSH set. This can avoid los-
ing a round trip time in some rare situations, but has
the caveat of potentially defeating TCP's delayed ACK al-
gorithm. Use of this option is generally not recommend-
ed, but the variable exists in case your configuration
really needs it.
tcp.keepidle
Time a connection must be idle before keepalives are sent
(if keepalives are enabled for the connection). See also
tcp.slowhz.
tcp.keepintvl
Time after a keepalive probe is sent until, in the ab-
sence of any response, another probe is sent. See also
tcp.slowhz.
tcp.keepcnt
Number of keepalive probes sent before declaring a con-
nection dead. If set to zero, there is no limit;
keepalives will be sent until some kind of response is
received from the peer.
tcp.slowhz
The units for tcp.keepidle and tcp.keepintvl; those vari-
ables are in ticks of a clock that ticks tcp.slowhz times
per second. (That is, their values must be divided by
the tcp.slowhz value to get times in seconds.)
tcp.newreno
Returns 1 if the use of J. Hoe's NewReno congestion con-
trol algorithm is enabled. This algorithm improves the
start-up behavior of TCP connections.
udp.checksum
Returns 1 when UDP checksums are being computed and
checked. Disabling UDP checksums is strongly discour-
aged.
udp.sendspace
Returns the default UDP send buffer size.
udp.recvspace
Returns the default UDP receive buffer size.
CTL_USER
The string and integer information available for the CTL_USER level is
detailed below. The changeable column shows whether a process with ap-
propriate privilege may change the value.
Second level name Type Changeable
USER_BC_BASE_MAX integer no
USER_BC_DIM_MAX integer no
USER_BC_SCALE_MAX integer no
USER_BC_STRING_MAX integer no
USER_COLL_WEIGHTS_MAX integer no
USER_CS_PATH string no
USER_EXPR_NEST_MAX integer no
USER_LINE_MAX integer no
USER_POSIX2_CHAR_TERM integer no
USER_POSIX2_C_BIND integer no
USER_POSIX2_C_DEV integer no
USER_POSIX2_FORT_DEV integer no
USER_POSIX2_FORT_RUN integer no
USER_POSIX2_LOCALEDEF integer no
USER_POSIX2_SW_DEV integer no
USER_POSIX2_UPE integer no
USER_POSIX2_VERSION integer no
USER_RE_DUP_MAX integer no
USER_STREAM_MAX integer no
USER_TZNAME_MAX integer no
USER_BC_BASE_MAX
The maximum ibase/obase values in the bc(1) utility.
USER_BC_DIM_MAX
The maximum array size in the bc(1) utility.
USER_BC_SCALE_MAX
The maximum scale value in the bc(1) utility.
USER_BC_STRING_MAX
The maximum string length in the bc(1) utility.
USER_COLL_WEIGHTS_MAX
The maximum number of weights that can be assigned to any entry
of the LC_COLLATE order keyword in the locale definition file.
USER_CS_PATH
Return a value for the PATH environment variable that finds all
the standard utilities.
USER_EXPR_NEST_MAX
The maximum number of expressions that can be nested within
parenthesis by the expr(1) utility.
USER_LINE_MAX
The maximum length in bytes of a text-processing utility's input
line.
USER_POSIX2_CHAR_TERM
Return 1 if the system supports at least one terminal type capa-
ble of all operations described in POSIX 1003.2, otherwise 0.
USER_POSIX2_C_BIND
Return 1 if the system's C-language development facilities sup-
port the C-Language Bindings Option, otherwise 0.
USER_POSIX2_C_DEV
Return 1 if the system supports the C-Language Development Utili-
ties Option, otherwise 0.
USER_POSIX2_FORT_DEV
Return 1 if the system supports the FORTRAN Development Utilities
Option, otherwise 0.
USER_POSIX2_FORT_RUN
Return 1 if the system supports the FORTRAN Runtime Utilities Op-
tion, otherwise 0.
USER_POSIX2_LOCALEDEF
Return 1 if the system supports the creation of locales, other-
wise 0.
USER_POSIX2_SW_DEV
Return 1 if the system supports the Software Development Utili-
ties Option, otherwise 0.
USER_POSIX2_UPE
Return 1 if the system supports the User Portability Utilities
Option, otherwise 0.
USER_POSIX2_VERSION
The version of POSIX 1003.2 with which the system attempts to
comply.
USER_RE_DUP_MAX
The maximum number of repeated occurrences of a regular expres-
sion permitted when using interval notation.
USER_STREAM_MAX
The minimum maximum number of streams that a process may have
open at any one time.
USER_TZNAME_MAX
The minimum maximum number of types supported for the name of a
timezone.
CTL_VM
The string and integer information available for the CTL_VM level is de-
tailed below. The changeable column shows whether a process with appro-
priate privilege may change the value.
Second level name Type Changeable
VM_LOADAVG struct loadavg no
VM_METER struct vmtotal no
VM_LOADAVG
Return the load average history. The returned data consists of a
struct loadavg.
VM_METER
Return the system wide virtual memory statistics. The returned
data consists of a struct vmtotal.
CTL_DDB
The integer information available for the CTL_DDB level is detailed be-
low. The changeable column shows whether a process with appropriate
privilege may change the value.
Second level name Type Changeable
DBCTL_RADIX integer yes
DBCTL_MAXOFF integer yes
DBCTL_LINES integer yes
DBCTL_TABSTOPS integer yes
DBCTL_ONPANIC integer yes
DBCTL_RADIX
The input and output radix.
DBCTL_MAXOFF
The maximum symbol offset.
DBCTL_LINES
Number of display lines.
DBCTL_TABSTOPS
Tab width.
DBCTL_ONPANIC
If non-zero, DDB will be entered when the kernel panics.
These MIB nodes are also available as variables from within the DDB. See
ddb(4) for more details.
RETURN VALUES
If the call to sysctl is successful, the number of bytes copied out is
returned. Otherwise -1 is returned and errno is set appropriately.
ERRORS
The following errors may be reported:
[EFAULT] The buffer name, oldp, newp, or length pointer oldlenp con-
tains an invalid address.
[EINVAL] The name array is less than two or greater than CTL_MAX-
NAME.
[EINVAL] A non-null newp is given and its specified length in newlen
is too large or too small.
[ENOMEM] The length pointed to by oldlenp is too short to hold the
requested value.
[ENOTDIR] The name array specifies an intermediate rather than termi-
nal name.
[EOPNOTSUPP] The name array specifies a value that is unknown.
[EPERM] An attempt is made to set a read-only value.
[EPERM] A process without appropriate privilege attempts to set a
value.
[EPERM] An attempt to change a value protected by the current ker-
nel security level is made.
FILES
<sys/sysctl.h> definitions for top level identifiers, second level
kernel and hardware identifiers, and user level
identifiers
<sys/socket.h> definitions for second level network identifiers
<sys/gmon.h> definitions for third level profiling identifiers
<vm/vm_param.h> definitions for second level virtual memory identi-
fiers
<netinet/in.h> definitions for third level Internet identifiers
and fourth level IP identifiers
<netinet/icmp_var.h> definitions for fourth level ICMP identifiers
<netinet/tcp_var.h> definitions for fourth level TCP identifiers
<netinet/udp_var.h> definitions for fourth level UDP identifiers
SEE ALSO
sysctl(8)
HISTORY
The sysctl function first appeared in 4.4BSD.
NetBSD 1.4 May 9, 1995 14
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