.\"     $NetBSD: getiobuf.9,v 1.3 2008/05/06 11:32:47 yamt Exp $
.\"
.\" Copyright (c)2006,2008 YAMAMOTO Takashi,
.\" All rights reserved.
.\"
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.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" ------------------------------------------------------------
.Dd May 6, 2008
.Dt GETIOBUF 9
.Os
.Sh NAME
.Nm getiobuf ,
.Nm putiobuf
.Nd I/O descriptor allocation interface
.\" ------------------------------------------------------------
.Sh SYNOPSIS
.In sys/buf.h
.Ft struct buf *
.Fn getiobuf "struct vnode *vp" "bool waitok"
.Ft void
.Fn putiobuf "struct buf *bp"
.\" ------------------------------------------------------------
.Sh DESCRIPTION
.Bl -tag -width compact
.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
.Fn getiobuf
allocates a
.Em buf
structure.
.Pp
.Bl -tag -width waitok
.It Fa vp
The vnode to which the allocated buffer will be associated.
This can be
.Dv NULL .
.It Fa waitok
If true,
.Fa getiobuf
can sleep until enough memory is available.
Otherwise, it returns
.Dv NULL
immediately if enough memory is not available.
.El
.Pp
Note that the allocated buffer doesn't belong to buffer cache.
To free it,
.Fn putiobuf
should be used.
.Fn brelse
should not be used on it.
.Pp
.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
.Fn putiobuf
frees
.Fa bp ,
which should be a buffer allocated with
.Fn getiobuf .
.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
.El
.\" ------------------------------------------------------------
.Sh SEE ALSO
.Xr buffercache 9 ,
.Xr intro 9