SWAPON(2)		  FreeBSD System Calls Manual		     SWAPON(2)

NAME
     swapon - add a swap device for interleaved paging/swapping

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     int
     swapon(const char *special);

DESCRIPTION
     Swapon() makes the block device special available to the system for allo-
     cation 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 VALUES
     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.

     [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 translat-
			ing 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 asso-
			ciated hardware).

     [EIO]		An I/O error occurred while opening the swap device.

     [EFAULT]		Special points outside the process's allocated address
			space.

SEE ALSO
     config(8), swapon(8)

BUGS
     There is no way to stop swapping on a disk so that the pack may be dis-
     mounted.

     This call will be upgraded in future versions of the system.

HISTORY
     The swapon() function call appeared in 4.0BSD.

FreeBSD 4.8			 June 4, 1993			   FreeBSD 4.8