SWAPON(2) BSD Programmer's Manual SWAPON(2)
swapon - add a swap device for interleaved paging/swapping
swapon(const char *special);
Swapon() makes the block device special available to the system for allo-
cation for paging and swapping. The names of potentially available de-
vices 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.
If an error has occurred, a value of -1 is returned and errno is set to
indicate the error.
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
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
[ELOOP] Too many symbolic links were encountered in translating the
[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 hard-
[EIO] An I/O error occurred while opening the swap device.
[EFAULT] Special points outside the process's allocated address
There is no way to stop swapping on a disk so that the pack may be dis-
This call will be upgraded in future versions of the system.
The swapon function call appeared in 4.0BSD.
4th Berkeley Distribution June 4, 1993 2