'\" te
.\"  Copyright 1989 AT&T
.\" Copyright (c) 2006, 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.
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.TH BTOP 9F "Jan 16, 2006"
.SH NAME
btop \- convert size in bytes to size in pages (round down)
.SH SYNOPSIS
.LP
.nf
#include <sys/ddi.h>



\fBunsigned long\fR \fBbtop\fR(\fBunsigned long\fR \fInumbytes\fR);
.fi

.SH INTERFACE LEVEL
.sp
.LP
Architecture independent level 1 (DDI/DKI).
.SH PARAMETERS
.sp
.ne 2
.na
\fB\fInumbytes\fR\fR
.ad
.RS 12n
Number of bytes.
.RE

.SH DESCRIPTION
.sp
.LP
The \fBbtop()\fR function returns the number of memory pages that are contained
in the specified number of bytes, with downward rounding in the case that the
byte count is not a page multiple. For example, if the page size is \fB2048\fR,
then \fBbtop(4096)\fR returns \fB2\fR, and \fBbtop(4097)\fR returns \fB2\fR as
well. \fBbtop(0)\fR returns \fB0\fR.
.SH RETURN VALUES
.sp
.LP
The return value is always the number of pages. There are no invalid input
values, and therefore no error return values.
.SH CONTEXT
.sp
.LP
The \fBbtop()\fR function can be called from user, interrupt, or kernel
context.
.SH SEE ALSO
.sp
.LP
.BR btopr (9F),
.BR ddi_btop (9F),
.BR ptob (9F)
.sp
.LP
\fIWriting Device Drivers\fR