swapon(2) [bsd man page]
SWAPON(2) System Calls Manual SWAPON(2) NAME
swapon - add a swap device for interleaved paging/swapping SYNOPSIS
swapon(special) char *special; DESCRIPTION
Swapon makes the block device special available to the system for allocation for paging and swapping. The names of potentially available devices are known to the system and defined at system configuration time. The size of the swap area on special is calculated at the time the device is first made available for swapping. RETURN VALUE
If an error has occurred, a value of -1 is returned and errno is set to indicate the error. ERRORS
Swapon succeeds unless: [ENOTDIR] A component of the path prefix is not a directory. [EINVAL] The pathname contains a character with the high-order bit set. [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters. [ENOENT] The named device does not exist. [EACCES] Search permission is denied for a component of the path prefix. [ELOOP] Too many symbolic links were encountered in translating the pathname. [EPERM] The caller is not the super-user. [ENOTBLK] Special is not a block device. [EBUSY] The device specified by special has already been made available for swapping [EINVAL] The device configured by special was not configured into the system as a swap device. [ENXIO] The major device number of special is out of range (this indicates no device driver exists for the associated hardware). [EIO] An I/O error occurred while opening the swap device. [EFAULT] Special points outside the process's allocated address space. SEE ALSO
swapon(8), config(8) BUGS
There is no way to stop swapping on a disk so that the pack may be dismounted. This call will be upgraded in future versions of the system. 4th Berkeley Distribution March 9, 1986 SWAPON(2)
Check Out this Related Man Page
SWAPON(2) BSD System Calls Manual SWAPON(2) NAME
swapon, swapoff -- control devices for interleaved paging/swapping LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <unistd.h> int swapon(const char *special); int swapoff(const char *special); DESCRIPTION
The swapon() system call makes the block device special available to the system for allocation for paging and swapping. The names of poten- tially available devices are known to the system and defined at system configuration time. The size of the swap area on special is calcu- lated at the time the device is first made available for swapping. The swapoff() system call disables paging and swapping on the given device. All associated swap metadata are deallocated, and the device is made available for other purposes. RETURN VALUES
If an error has occurred, a value of -1 is returned and errno is set to indicate the error. ERRORS
Both swapon() and swapoff() can fail if: [ENOTDIR] A component of the path prefix is not a directory. [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters. [ENOENT] The named device does not exist. [EACCES] Search permission is denied for a component of the path prefix. [ELOOP] Too many symbolic links were encountered in translating the pathname. [EPERM] The caller is not the super-user. [EFAULT] The special argument points outside the process's allocated address space. Additionally, swapon() can fail for the following reasons: [ENOTBLK] The special argument is not a block device. [EBUSY] The device specified by special has already been made available for swapping [ENXIO] The major device number of special is out of range (this indicates no device driver exists for the associated hardware). [EIO] An I/O error occurred while opening the swap device. Lastly, swapoff() can fail if: [EINVAL] The system is not currently swapping to special. [ENOMEM] Not enough virtual memory is available to safely disable paging and swapping to the given device. SEE ALSO
config(8), swapon(8), sysctl(8) HISTORY
The swapon() system call appeared in 4.0BSD. The swapoff() system call appeared in FreeBSD 5.0. BSD
October 4, 2013 BSD