xref: /freebsd/share/man/man9/vref.9 (revision 8d20be1e22095c27faf8fe8b2f0d089739cc742e)
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29.\" $FreeBSD$
30.\"
31.Dd July 24, 1996
32.Dt VREF 9
33.Os
34.Sh NAME
35.Nm vref
36.Nd increment the use count for a vnode
37.Sh SYNOPSIS
38.In sys/param.h
39.In sys/vnode.h
40.Ft void
41.Fn vref "struct vnode *vp"
42.Sh DESCRIPTION
43Increment the
44.Va v_usecount
45field of a vnode.
46.Bl -tag -width 2n
47.It Fa vp
48the vnode to increment
49.El
50.Pp
51Each vnode maintains a reference count of how many parts of the system
52are using the vnode.
53This allows the system to detect when a vnode is
54no longer being used and can be safely recycled for a different file.
55.Pp
56Any code in the system which is using a vnode (e.g.\& during the
57operation of some algorithm or to store in a data structure) should
58call
59.Fn vref .
60.Sh SEE ALSO
61.Xr vget 9 ,
62.Xr vnode 9 ,
63.Xr vput 9 ,
64.Xr vrefcnt 9 ,
65.Xr vrele 9
66.Sh AUTHORS
67This manual page was written by
68.An Doug Rabson .
69