btop(9F) Kernel Functions for Drivers btop(9F)
NAME
btop - convert size in bytes to size in pages (round down)
SYNOPSIS
#include <sys/ddi.h>
unsigned long btop(unsigned long numbytes);
INTERFACE LEVEL
Architecture independent level 1 (DDI/DKI).
PARAMETERS
numbytes Number of bytes.
DESCRIPTION
The btop() 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 2048, then btop(4096) returns 2, and btop(4097) returns 2
as well. btop(0) returns 0.
RETURN VALUES
The return value is always the number of pages. There are no invalid input values, and therefore no error return values.
CONTEXT
The btop() function can be called from user, interrupt, or kernel context.
SEE ALSO
btopr(9F), ddi_btop(9F), ptob(9F)
Writing Device Drivers
SunOS 5.11 16 Jan 2006 btop(9F)
