'\" te
.\" Copyright (c) 2008, Sun Microsystems, Inc. All Rights Reserved.
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE.  If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
.TH READ_VTOC 3EXT "Oct 7, 2008"
.SH NAME
read_vtoc, write_vtoc \- read and write a disk's VTOC
.SH SYNOPSIS
.LP
.nf
\fBcc\fR [ \fIflag\fR ... ] \fIfile\fR ... \fB-ladm\fR [ \fIlibrary\fR ... ]
#include <sys/vtoc.h>

\fBint\fR \fBread_vtoc\fR(\fBint\fR \fIfd\fR, \fBstruct vtoc *\fR\fIvtoc\fR);
.fi

.LP
.nf
\fBint\fR \fBwrite_vtoc\fR(\fBint\fR \fIfd\fR, \fBstruct vtoc *\fR\fIvtoc\fR);
.fi

.LP
.nf
\fBint\fR \fBread_extvtoc\fR(\fBint\fR \fIfd\fR, \fBstruct extvtoc *\fR\fIextvtoc\fR);
.fi

.LP
.nf
\fBint\fR \fBwrite_extvtoc\fR(\fBint\fR \fIfd\fR, \fBstruct extvtoc *\fR\fIextvtoc\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBread_vtoc()\fR and \fBread_extvtoc()\fR functions return the VTOC
(volume  table  of contents)  structure  that is stored on  the disk associated
with the open file descriptor \fIfd\fR. On disks larger than 1 TB
\fBread_extvtoc()\fR must be used.
.sp
.LP
The \fBwrite_vtoc()\fR and \fBwrite_extvtoc()\fR function stores the VTOC
structure on the disk associated with the open file descriptor \fIfd\fR. On
disks larger then 1TB \fBwrite_extvtoc()\fR function must be used.
.sp
.LP
The \fIfd\fR argument refers to any slice on a raw disk.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, \fBread_vtoc()\fR and \fBread_extvtoc()\fR return a
positive integer indicating the slice index associated with the open file
descriptor. Otherwise, they return a negative integer indicating one of the
following errors:
.sp
.ne 2
.na
\fB\fBVT_EIO\fR\fR
.ad
.RS 15n
An I/O error occurred.
.RE

.sp
.ne 2
.na
\fB\fBVT_ENOTSUP\fR\fR
.ad
.RS 15n
This operation is not supported on this disk.
.RE

.sp
.ne 2
.na
\fB\fBVT_ERROR\fR\fR
.ad
.RS 15n
An unknown error occurred.
.RE

.sp
.ne 2
.na
\fB\fBVT_OVERFLOW\fR\fR
.ad
.RS 15n
The caller attempted an operation that is illegal on the disk and may overflow
the fields in the data structure.
.RE

.sp
.LP
Upon successful completion, \fBwrite_vtoc()\fR and \fBwrite_extvtoc()\fR return
0. Otherwise, they return a negative integer indicating one of the following
errors:
.sp
.ne 2
.na
\fB\fBVT_EINVAL\fR\fR
.ad
.RS 15n
The VTOC contains an incorrect field.
.RE

.sp
.ne 2
.na
\fB\fBVT_EIO\fR\fR
.ad
.RS 15n
An I/O error occurred.
.RE

.sp
.ne 2
.na
\fB\fBVT_ENOTSUP\fR\fR
.ad
.RS 15n
This operation is not supported on this disk.
.RE

.sp
.ne 2
.na
\fB\fBVT_ERROR\fR\fR
.ad
.RS 15n
An unknown error occurred.
.RE

.sp
.ne 2
.na
\fB\fBVT_OVERFLOW\fR\fR
.ad
.RS 15n
The caller attempted an operation that is illegal on the disk and may overflow
the fields in the data structure.
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
MT-Level	Unsafe
.TE

.SH SEE ALSO
.sp
.LP
\fBfmthard\fR(1M), \fBformat\fR(1M), \fBprtvtoc\fR(1M), \fBioctl\fR(2),
\fBefi_alloc_and_init\fR(3EXT), \fBattributes\fR(5), \fBdkio\fR(7I)
.SH BUGS
.sp
.LP
The \fBwrite_vtoc()\fR function cannot write a  \fBVTOC\fR on an unlabeled
disk. Use \fBformat\fR(1M) for this purpose.