round_page(9r)round_page(9r)NAMEround_page - General: Rounds the specified address
SYNOPSIS
#include <mach/vm_param.h>
vm_offset_t round_page(
vm_offset_t address );
ARGUMENTS
Specifies the address (or byte count) that is being rounded.
DESCRIPTION
The round_page routine rounds the specified address (or byte count) to
a multiple of the page size. For example, round_page would round a
1-byte count to be equal to the size of one page. This routine shields
the driver writer from having to know the page size of the system,
which could vary in different CPU architectures and on different CPU
types within the same architecture. Typically, a device driver calls
round_page in preparation for doing a DMA operation to a user's buffer.
The value returned by this routine is used in the call to the
vm_map_pageable routine. To use this routine, the driver writer must
include the <mach/vm_param.h> header file in the driver.
RETURN VALUES
The round_page routine returns the rounded address or byte count.
SEE ALSO
Routines: current_task(9r), trunc_page(9r), vm_map_pageable(9r)round_page(9r)