trunc_page(9r)trunc_page(9r)NAMEtrunc_page - General: Truncates the specified address
SYNOPSIS
#include <mach/vm_param.h>
vm_offset_t trunc_page(
vm_offset_t address );
ARGUMENTS
Specifies the address that is being truncated to a page boundary.
DESCRIPTION
The trunc_page routine truncates the specified address to be aligned on
a page boundary. 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 trunc_page in preparation for doing a
DMA operation on 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 trunc_page routine returns an address truncated to a page boundary.
SEE ALSO
Routines: current_task(9r), round_page(9r), vm_map_pageable(9r)trunc_page(9r)