swapon(2)swapon(2)NAMEswapon - Add a swap device for interleaved paging and swapping
SYNOPSIS
int swapon(
char *pat,
int options,
int lowat,
int hiwat );
PARAMETERS
Specifies the block special device to be made available. Specifies an
option. Only the MS_PREFER option is currently supported, and it
causes the specified path to be the preferred paging device. (Ignored
on Tru64 UNIX systems.) Specifies the low water mark. (Ignored on
Tru64 UNIX systems.) Specifies the high water mark. (Ignored on Tru64
UNIX systems.)
DESCRIPTION
The swapon() function makes a block special device available to the
system for allocation of paging and swapping space. (The operating sys‐
tem does not currently support paging and swapping to a normal file.
All swapping and paging areas must be block special devices.)
The calling process must have superuser privilege to call the swapon()
function.
RETURN VALUES
Upon successful completion, the swapon() function returns a value of 0
(zero). If an error has occurred, -1 is returned and errno is set to
indicate the error.
ERRORS
If the swapon() function fails, errno may be set to one of the follow‐
ing values: Search permission is denied for a component of the path
prefix. The device specified by the path parameter has already been
made available for swapping. The path parameter points outside the
process' allocated address space. The pathname contains a character
with the high-order bit set, the device was not specified, the device
configured by the path parameter was not configured into the system as
a swap device, or the device does not allow paging. An I/O error
occurred while opening the swap device. Too many symbolic links were
encountered in translating the pathname. A component of a pathname
exceeded NAME_MAX characters, or an entire pathname exceeded PATH_MAX
characters. The named device does not exist. A component of the path
prefix is not a directory. The major device number of the path parame‐
ter is out of range. (This indicates that no device driver exists for
the associated hardware.) The caller does not have appropriate privi‐
lege. An attempt was made to activate a paging file on a read-only
file system.
SEE ALSO
Commands: config(8), swapon(8)swapon(2)