swapon.2 (2010 09)

ManualsBrandsHP ManualsSoftwareHP-UX Manpages

swapon(2) swapon(2)

(TO BE OBSOLETED)

NAME

swapon() - add swap space for interleaved paging and swapping

SYNOPSIS

#include <unistd.h>

int swapon(const char *path, ...

/* [int min,

int limit,

int reserve,]

int priority */ );

Remarks

The ANSI C ", ..." construct denotes a variable length argument list whose optional and required

members are given in the associated comment (

/* */).

DESCRIPTION

The

swapon() system call makes a block device or a directory named path available to the system for

paging and swapping.

priority indicates the order in which the swap space from the device or ﬁle system is used. It has a range

of 0 (highest) to 10 (lowest). Space is taken from the lower-numbered systems ﬁrst.

swapon() can be used only by users who have appropriate privileges.

If path names a block device ﬁle

swapon() makes it available to the system at the speciﬁed priority for allocation for paging and swap-

ping.

In this form,

swapon() takes only two arguments: the path to the block device ﬁle, and the priority .

The device associated with path can be a device already known to the system, deﬁned at system

conﬁguration time, or it can be a previously unspeciﬁed device.

If the device was already deﬁned at system conﬁguration time and also has a start and/or size deﬁned for

that swap device, these values are used.

Otherwise, if a ﬁlesystem exists on the device, swap is added following the ﬁlesystem, or if no ﬁlesystem

exists, the complete device is used for swap.

See the appropriate system administrator’s manual for information on how the size of the swap area is

calculated.

If path names a directory

swapon() makes the blocks on the ﬁle system rooted at path available for paging and swapping.

The min, limit , and reserve arguments are passed and used only if the path argument names a directory.

min indicates the number of ﬁle system blocks to take from the ﬁle system when

swapon() is called.

limit indicates the maximum number of ﬁle system blocks the swap system is allowed to take from the ﬁle

system.

reserve indicates the number of ﬁle system blocks that are saved for ﬁle system use only.

For a pre-existing directory swap, a value of -1 for min, limit , reserve ,orpriority will keep the value

unchanged. This can be used to change selective values without affecting others. For example, if priority

of a pre-existing directory swap needs to be changed without affecting the values of min, limit ,orreserve ,

one can specify the new priority value and pass -1 for other arguments.

The size for the ﬁle system blocks mentioned above is the preferred ﬁle system block size. The preferred

ﬁle system block size can be obtained by the

statvfs() call. The value of min, limit ,orreserve is

rounded up to the swchunk tunable size.

ERRORS

swapon() fails, errno is set to one of the following values.

[EACCES] A component of the path preﬁx denies search permission.

[EINVAL] One of priority , min, limit ,orreserve arguments is invalid.

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (2 pages)

PAGE 1
swapon(2) swapon(2) (TO BE OBSOLETED) NAME swapon() - add swap space for interleaved paging and swapping SYNOPSIS #include int swapon(const char *path, ... /* [int min, int limit, int reserve,] int priority */ ); Remarks The ANSI C ", ..." construct denotes a variable length argument list whose optional and required members are given in the associated comment (/* */).
PAGE 2
swapon(2) swapon(2) (TO BE OBSOLETED) [EALREADY] The device associated with path already has swap turned on. [EBUSY] The device associated with path is already in use. [EEXIST] The device associated with path was specified at system configuration time to add swap at a specified location, but that location is within an existing file system on the device. [EFAULT] The LIF header on the device associated with path contains inconsistent directory data.