freebsd-skq/share/man/man9/vref.9

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.\" -*- nroff -*-
.\"
.\" Copyright (c) 1996 Doug Rabson
.\"
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.\" This program is free software.
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1999-08-28 00:22:10 +00:00
.\" $FreeBSD$
.\"
.Dd July 24, 1996
.Os
1997-03-22 22:47:34 +00:00
.Dt VREF 9
.Sh NAME
.Nm vref
.Nd increment the use count for a vnode
.Sh SYNOPSIS
.In sys/param.h
.In sys/vnode.h
.Ft void
.Fn vref "struct vnode *vp"
.Sh DESCRIPTION
Increment the
.Dv v_usecount
field of a vnode.
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.Bl -tag -width 2n
.It Ar vp
the vnode to increment
.El
.Pp
Each vnode maintains a reference count of how many parts of the system
are using the vnode. This allows the system to detect when a vnode is
no longer being used and can be safely recycled for a different file.
.Pp
Any code in the system which is using a vnode (e.g. during the
operation of some algorithm or to store in a data structure) should
call
.Xr vref 9 .
.Sh SEE ALSO
.Xr vget 9 ,
.Xr vnode 9 ,
.Xr vput 9 ,
.Xr vrele 9
.Sh AUTHORS
This man page was written by
.An Doug Rabson .