---
name: "sysctlbyname"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/sysctl/3"
---

# sysctlbyname(3)

get or set system information

Part of [sysctl(3)](/sysctl/3.md).

## NAME

**sysctl**, **sysctlbyname**, **sysctlnametomib** – get or set system information

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<sys/sysctl.h\>**

*int*\

**sysctl**(*const int \*name*, *u\_int namelen*, *void \*oldp*, *size\_t \*oldlenp*, *const void \*newp*, *size\_t newlen*);

*int*\

**sysctlbyname**(*const char \*name*, *void \*oldp*, *size\_t \*oldlenp*, *const void \*newp*, *size\_t newlen*);

*int*\

**sysctlnametomib**(*const char \*name*, *int \*mibp*, *size\_t \*sizep*);

## 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. Information may be retrieved and set from the command interface using the [sysctl(8)](/sysctl/8.md) 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 **sysctlbyname**() function accepts an ASCII representation of the name and internally looks up the integer name vector. Apart from that, it behaves the same as the standard **sysctl**() function.

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 and after a call that returns with the error code ENOMEM. 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 the NULL argument 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 **sysctlnametomib**() function accepts an ASCII representation of the name, looks up the integer name vector, and returns the numeric representation in the mib array pointed to by *mibp*. The number of elements in the mib array is given by the location specified by *sizep* before the call, and that location gives the number of entries copied after a successful call. The resulting *mib* and *size* may be used in subsequent **sysctl**() calls to get the data associated with the requested ASCII name. This interface is intended for use by applications that want to repeatedly request the same variable (the **sysctl**() function runs in about a third the time as the same request made via the **sysctlbyname**() function). The **sysctlnametomib**() function is also useful for fetching mib prefixes and then adding a final component. For example, to fetch process information for processes with pid's less than 100:

```
int i, mib[4];
size_t len;
struct kinfo_proc kp;
/* Fill out the first three components of the mib */
len = 4;
sysctlnametomib("kern.proc.pid", mib, &len);
/* Fetch and print entries for pid's < 100 */
for (i = 0; i < 100; i++) {
	mib[3] = i;
	len = sizeof(kp);
	if (sysctl(mib, 4, &kp, &len, NULL, 0) == -1)
		perror("sysctl");
	else if (len > 0)
		printkproc(&kp);
}
```

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 include files listed here, and described in separate sections below.

| | | |
| --- | --- | --- |
| **Name** | **Next** **Level** **Names** | **Description** |
| CTL\_DEBUG | In sys/sysctl.h | Debugging |
| CTL\_VFS | In sys/mount.h | File system |
| CTL\_HW | In sys/sysctl.h | Generic CPU, I/O |
| CTL\_KERN | In sys/sysctl.h | High kernel limits |
| CTL\_MACHDEP | In sys/sysctl.h | Machine dependent |
| CTL\_NET | In sys/socket.h | Networking |
| CTL\_USER | In sys/sysctl.h | User-level |
| CTL\_VM | In vm/vm\_param.h | Virtual memory |

For example, the following retrieves the maximum number of processes allowed 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 declared as separate variables so that they can be individually initialized at the location of their associated variable. The loader prevents multiple use of the same variable by issuing errors if a variable is initialized 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 file systems. One of its third level identifiers is VFS\_MAXTYPENUM that gives the highest valid file system type number. Its other third level identifier is VFS\_CONF that returns configuration information about the file system type given as a fourth level identifier (see [getvfsbyname(3)](/getvfsbyname/3.md) as an example of its use). The remaining second level identifiers are the file system type number returned by a [statfs(2)](/statfs/2.md) call or from VFS\_CONF. The third level identifiers available for each file system are given in the header file that defines the mount argument structure for that file system.

### CTL\_HW

The string and integer information available for the CTL\_HW level is detailed below. The changeable column shows whether a process with appropriate 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\_FLOATINGPT | integer | no |
| HW\_MACHINE\_ARCH | string | no |
| HW\_REALMEM | integer | no |
| HW\_AVAILPAGES | integer | no |

- HW\_MACHINE

  The machine class.

- HW\_MODEL

  The machine model

- HW\_NCPU

  The number of cpus.

- HW\_BYTEORDER

  The byteorder (4321 or 1234).

- HW\_PHYSMEM

  Amount of physical memory (in bytes), minus the amount used by the kernel, pre-loaded modules, and (on x86) the dcons buffer.

- HW\_USERMEM

  Amount of memory (in bytes) which is not wired.

- HW\_PAGESIZE

  The software page size.

- HW\_FLOATINGPT

  Nonzero if the floating point support is in hardware.

- HW\_MACHINE\_ARCH

  The machine dependent architecture type.

- HW\_REALMEM

  Amount of memory (in bytes) reported by the firmware. That value is sometimes not sane; in that case, the kernel reports the max memory address instead.

- HW\_AVAILPAGES

  The same value as HW\_PHYSMEM, measured in pages rather than bytes.

### CTL\_KERN

The string and integer information available for the CTL\_KERN level is detailed below. The changeable column shows whether a process with appropriate 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\_ARND | byte buffer | no |
| KERN\_BOOTFILE | string | yes |
| KERN\_BOOTTIME | struct timeval | no |
| KERN\_CLOCKRATE | struct clockinfo | no |
| KERN\_FILE | struct xfile | no |
| KERN\_HOSTID | integer | yes |
| KERN\_HOSTUUID | string | yes |
| KERN\_HOSTNAME | string | yes |
| KERN\_IOV\_MAX | integer | no |
| KERN\_JOB\_CONTROL | integer | no |
| KERN\_LOCKF | struct kinfo\_lockf | no |
| KERN\_LOGSIGEXIT | integer | yes |
| KERN\_MAXFILES | integer | yes |
| KERN\_MAXFILESPERPROC | integer | yes |
| KERN\_MAXPHYS | integer | no |
| KERN\_MAXPROC | integer | no |
| KERN\_MAXPROCPERUID | integer | yes |
| KERN\_MAXVNODES | integer | yes |
| KERN\_NGROUPS | integer | no |
| KERN\_NISDOMAINNAME | string | yes |
| KERN\_OSRELDATE | integer | no |
| KERN\_OSRELEASE | string | no |
| KERN\_OSREV | integer | no |
| KERN\_OSTYPE | string | no |
| KERN\_POSIX1 | integer | no |
| KERN\_PROC | node | not applicable |
| KERN\_PS\_STRINGS | integer | no |
| KERN\_SAVED\_IDS | integer | no |
| KERN\_SECURELVL | integer | raise only |
| KERN\_UPDATEINTERVAL | integer | no |
| KERN\_USRSTACK | integer | no |
| KERN\_VERSION | string | no |

- KERN\_ARGMAX

  The maximum bytes of argument to [execve(2)](/execve/2.md).

- KERN\_ARND

  [arc4rand(9)](/arc4rand/9.md) Fills the buffer with random bytes from in-kernel random data generator. This is an alternative interface for [read(2)](/read/2.md) of [random(4)](/random/4.md) device, which does not depend on accessibility and correct mounting options of the [devfs(4)](/devfs/4.md) node.

- KERN\_BOOTFILE

  The full pathname of the file from which the kernel was loaded.

- KERN\_BOOTTIME

  A *struct* *timeval* structure is returned. This structure contains the time that the system was booted.

- KERN\_CLOCKRATE

  A *struct* *clockinfo* structure is returned. This structure contains the clock, statistics clock and profiling clock frequencies, the number of micro-seconds per hz tick and the skew rate.

- KERN\_FILE

  Return the entire file table. The returned data consists of an array of *struct* *xfile*, whose size depends on the current number of such objects in the system.

- KERN\_HOSTID

  Get or set the host ID.

- KERN\_HOSTUUID

  Get or set the host's universally unique identifier (UUID).

- KERN\_HOSTNAME

  Get or set the hostname.

- KERN\_IOV\_MAX

  The maximum accepted number of elements in an input-output vector (iovec), see [readv(2)](/readv/2.md) and [writev(2)](/writev/2.md).

- KERN\_JOB\_CONTROL

  Return 1 if job control is available on this system, otherwise 0.

- KERN\_LOCKF

  Returns the list of the file advisory locks currently known to kernel.

- KERN\_LOGSIGEXIT

  Controls logging of process exit due to untrapped signals.

- KERN\_MAXFILES

  The maximum number of files that may be open in the system.

- KERN\_MAXFILESPERPROC

  The maximum number of files that may be open for a single process. This limit only applies to processes with an effective uid of nonzero at the time of the open request. Files that have already been opened are not affected if the limit or the effective uid is changed.

- KERN\_MAXPHYS

  Specifies the maximum block I/O size. Can be changed by the tunable kern.maxphys.

- KERN\_MAXPROC

  The maximum number of concurrent processes the system will allow.

- KERN\_MAXPROCPERUID

  The maximum number of concurrent processes the system will allow for a single effective uid. This limit only applies to processes with an effective uid of nonzero at the time of a fork request. Processes that have already been started are not affected if the limit is changed.

- KERN\_MAXVNODES

  The maximum number of vnodes available on the system.

- KERN\_NGROUPS

  The maximum number of supplemental groups.

- KERN\_NISDOMAINNAME

  The name of the current YP/NIS domain.

- KERN\_OSRELDATE

  The kernel release version in the format *M**mm**R**xx*, where *M* is the major version, *mm* is the two digit minor version, *R* is 0 if release branch, otherwise 1, and *xx* is updated when the available APIs change.

  The userland release version is available from ⟨osreldate.h⟩; parse this file if you need to get the release version of the currently installed userland.

- KERN\_OSRELEASE

  The system release string.

- KERN\_OSREV

  The system revision number.

- KERN\_OSTYPE

  The system type string.

- KERN\_POSIX1

  The version of IEEE Std 1003.1 (“POSIX.1”) with which the system attempts to comply.

- KERN\_PROC

  Return selected information about specific running processes.

  For the following names, an array of *struct* *kinfo\_proc* structures is returned, whose size depends on the current number of such objects in the system.

  | | |
  | --- | --- |
  | **Third** **Level** **Name** | **Fourth** **Level** |
  | KERN\_PROC\_ALL | None |
  | KERN\_PROC\_PID | A process ID |
  | KERN\_PROC\_PGRP | A process group |
  | KERN\_PROC\_SESSION | A session |
  | KERN\_PROC\_TTY | A tty device |
  | KERN\_PROC\_UID | effective user ID |
  | KERN\_PROC\_RUID | A real user ID |
  | KERN\_PROC\_GID | effective group ID |
  | KERN\_PROC\_RGID | A real group ID |

- KERN\_PS\_STRINGS

  Reports the location of the process *ps\_strings* structure after exec, for the ABI of the querying process.

- 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 not be lowered.

- KERN\_USRSTACK

  Reports the top of the main thread user stack for the current process.

- KERN\_VERSION

  The system version string.

### CTL\_NET

The string and integer information available for the CTL\_NET level is detailed below. The changeable column shows whether a process with appropriate privilege may change the value.

| | | |
| --- | --- | --- |
| **Second** **Level** **Name** | **Type** | **Changeable** |
| PF\_ROUTE | routing messages | no |
| PF\_INET | IPv4 values | yes |
| PF\_INET6 | IPv6 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)](/route/4.md) 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 always 0. The fourth level name is an address family, which may be set to 0 to select all address families. The fifth, sixth, and seventh level names are as follows:

  | | | |
  | --- | --- | --- |
  | **Fifth** **level** | **Sixth** **Level** | **Seventh** **Level** |
  | NET\_RT\_FLAGS | rtflags | None |
  | NET\_RT\_DUMP | None | None or fib number |
  | NET\_RT\_IFLIST | 0 or if\_index | None |
  | NET\_RT\_IFMALIST | 0 or if\_index | None |
  | NET\_RT\_IFLISTL | 0 or if\_index | None |
  | NET\_RT\_NHOPS | None | fib number |

- PF\_INET

  Get or set various global information about the IPv4 (Internet Protocol version 4). The third level name is the protocol. The fourth level name is the variable name. The currently defined protocols and names are:

  | | | | |
  | --- | --- | --- | --- |
  | **Protocol** | **Variable** | **Type** | **Changeable** |
  | icmp | bmcastecho | integer | yes |
  | icmp | maskrepl | integer | yes |
  | ip | forwarding | integer | yes |
  | ip | redirect | integer | yes |
  | ip | ttl | integer | yes |
  | udp | checksum | integer | yes |

- PF\_INET6

  Get or set various global information about the IPv6 (Internet Protocol version 6). The third level name is the protocol. The fourth level name is the variable name.

  For variables net.inet6.\* please refer to [inet6(4)](/inet6/4.md). For variables net.inet6.\*.ipsec6, please refer to [ipsec(4)](/ipsec/4.md).

### CTL\_USER

The string and integer information available for the CTL\_USER level is detailed below. The changeable column shows whether a process with appropriate 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\_LOCALBASE | string | 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)](/bc/1.md) utility.

- USER\_BC\_DIM\_MAX

  The maximum array size in the [bc(1)](/bc/1.md) utility.

- USER\_BC\_SCALE\_MAX

  The maximum scale value in the [bc(1)](/bc/1.md) utility.

- USER\_BC\_STRING\_MAX

  The maximum string length in the [bc(1)](/bc/1.md) 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)](/expr/1.md) utility.

- USER\_LINE\_MAX

  The maximum length in bytes of a text-processing utility's input line.

- USER\_LOCALBASE

  Return the value of localbase that has been compiled into system utilities that need to have access to resources provided by a port or package.

- USER\_POSIX2\_CHAR\_TERM

  Return 1 if the system supports at least one terminal type capable of all operations described in IEEE Std 1003.2 (“POSIX.2”), otherwise 0.

- USER\_POSIX2\_C\_BIND

  Return 1 if the system's C-language development facilities support the C-Language Bindings Option, otherwise 0.

- USER\_POSIX2\_C\_DEV

  Return 1 if the system supports the C-Language Development Utilities 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 Option, otherwise 0.

- USER\_POSIX2\_LOCALEDEF

  Return 1 if the system supports the creation of locales, otherwise 0.

- USER\_POSIX2\_SW\_DEV

  Return 1 if the system supports the Software Development Utilities 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 IEEE Std 1003.2 (“POSIX.2”) with which the system attempts to comply.

- USER\_RE\_DUP\_MAX

  The maximum number of repeated occurrences of a regular expression 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 detailed below. The changeable column shows whether a process with appropriate privilege may change the value.

| | | |
| --- | --- | --- |
| **Second** **Level** **Name** | **Type** | **Changeable** |
| VM\_LOADAVG | struct loadavg | no |
| VM\_TOTAL | struct vmtotal | no |
| VM\_SWAPPING\_ENABLED | integer | maybe |
| VM\_V\_FREE\_MIN | integer | yes |
| VM\_V\_FREE\_RESERVED | integer | yes |
| VM\_V\_FREE\_TARGET | integer | yes |
| VM\_V\_INACTIVE\_TARGET | integer | yes |
| VM\_V\_PAGEOUT\_FREE\_MIN | integer | yes |
| VM\_OVERCOMMIT | integer | yes |

- VM\_LOADAVG

  Return the load average history. The returned data consists of a *struct* *loadavg*.

- VM\_TOTAL

  Return the system wide virtual memory statistics. The returned data consists of a *struct* *vmtotal*.

- VM\_SWAPPING\_ENABLED

  1 if process swapping is enabled or 0 if disabled. This variable is permanently set to 0 if the kernel was built with swapping disabled.

- VM\_V\_FREE\_MIN

  Minimum amount of memory (cache memory plus free memory) required to be available before a process waiting on memory will be awakened.

- VM\_V\_FREE\_RESERVED

  Processes will awaken the pageout daemon and wait for memory if the number of free and cached pages drops below this value.

- VM\_V\_FREE\_TARGET

  The total amount of free memory (including cache memory) that the pageout daemon tries to maintain.

- VM\_V\_INACTIVE\_TARGET

  The desired number of inactive pages that the pageout daemon should achieve when it runs. Inactive pages can be quickly inserted into process address space when needed.

- VM\_V\_PAGEOUT\_FREE\_MIN

  If the amount of free and cache memory falls below this value, the pageout daemon will enter "memory conserving mode" to avoid deadlock.

- VM\_OVERCOMMIT

  Overcommit behaviour, as described in [tuning(7)](/tuning/7.md).

## RETURN VALUES

The **sysctl()** function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

## FILES

- In sys/sysctl.h

  definitions for top level identifiers, second level kernel and hardware identifiers, and user level identifiers

- In sys/socket.h

  definitions for second level network identifiers

- In sys/gmon.h

  definitions for third level profiling identifiers

- In vm/vm\_param.h

  definitions for second level virtual memory identifiers

- In netinet/in.h

  definitions for third level IPv4/IPv6 identifiers and fourth level IPv4/v6 identifiers

- In netinet/icmp\_var.h

  definitions for fourth level ICMP identifiers

- In netinet/icmp6.h

  definitions for fourth level ICMPv6 identifiers

- In netinet/udp\_var.h

  definitions for fourth level UDP identifiers

## ERRORS

The following errors may be reported:

- \[EFAULT\]

  The buffer *name*, *oldp*, *newp*, or length pointer *oldlenp* contains an invalid address.

- \[EINVAL\]

  The *name* array is less than two or greater than CTL\_MAXNAME.

- \[EINVAL\]

  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.

- \[ENOMEM\]

  The smaller of either the length pointed to by *oldlenp* or the estimated size of the returned data exceeds the system limit on locked memory.

- \[ENOMEM\]

  Locking the buffer *oldp*, or a portion of the buffer if the estimated size of the data to be returned is smaller, would cause the process to exceed its per-process locked memory limit.

- \[ENOTDIR\]

  The *name* array specifies an intermediate rather than terminal name.

- \[EISDIR\]

  The *name* array specifies a terminal name, but the actual name is not terminal.

- \[ENOENT\]

  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.

- \[ECAPMODE\]

  The process is in capability mode and the variable is not accessible in capability mode.

## SEE ALSO

[confstr(3)](/confstr/3.md), [kinfo\_getproc(3)](/kinfo_getproc/3.md), [kvm(3)](/kvm/3.md), [sysconf(3)](/sysconf/3.md), [sysctl(8)](/sysctl/8.md)

## HISTORY

The **sysctl**() function first appeared in 4.4BSD.