1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)swapon.2 8.1 (Berkeley) 06/04/93 7.\" 8.Dd 9.Dt SWAPON 2 10.Os BSD 4 11.Sh NAME 12.Nm swapon 13.Nd add a swap device for interleaved paging/swapping 14.Sh SYNOPSIS 15.Fd #include <unistd.h> 16.Ft int 17.Fn swapon "const char *special" 18.Sh DESCRIPTION 19.Fn Swapon 20makes the block device 21.Fa special 22available to the system for 23allocation for paging and swapping. The names of potentially 24available devices are known to the system and defined at system 25configuration time. The size of the swap area on 26.Fa special 27is calculated at the time the device is first made available 28for swapping. 29.Sh RETURN VALUES 30If an error has occurred, a value of -1 is returned and 31.Va errno 32is set to indicate the error. 33.Sh ERRORS 34.Fn Swapon 35succeeds unless: 36.Bl -tag -width ENAMETOOLONG 37.It Bq Er ENOTDIR 38A component of the path prefix is not a directory. 39.It Bq Er EINVAL 40The pathname contains a character with the high-order bit set. 41.It Bq Er ENAMETOOLONG 42A component of a pathname exceeded 255 characters, 43or an entire path name exceeded 1023 characters. 44.It Bq Er ENOENT 45The named device does not exist. 46.It Bq Er EACCES 47Search permission is denied for a component of the path prefix. 48.It Bq Er ELOOP 49Too many symbolic links were encountered in translating the pathname. 50.It Bq Er EPERM 51The caller is not the super-user. 52.It Bq Er ENOTBLK 53.Fa Special 54is not a block device. 55.It Bq Er EBUSY 56The device specified by 57.Fa special 58has already 59been made available for swapping 60.It Bq Er EINVAL 61The device configured by 62.Fa special 63was not 64configured into the system as a swap device. 65.It Bq Er ENXIO 66The major device number of 67.Fa special 68is out of range (this indicates no device driver exists 69for the associated hardware). 70.It Bq Er EIO 71An I/O error occurred while opening the swap device. 72.It Bq Er EFAULT 73.Fa Special 74points outside the process's allocated address space. 75.Sh SEE ALSO 76.Xr swapon 8 , 77.Xr config 8 78.Sh BUGS 79There is no way to stop swapping on a disk so that the pack may be 80dismounted. 81.Pp 82This call will be upgraded in future versions of the system. 83.Sh HISTORY 84The 85.Nm 86function call appeared in 87.Bx 4.0 . 88