mirror of
https://github.com/opnsense/src.git
synced 2026-07-15 04:01:09 -04:00
24ea81047d
This new function computes the alignment of a pointer. It is part of ISO/IEC 9899:2024, the new C standard. If the pointer is a null pointer, null is returned. I have tried to write an implementation that can cope with traditional address-based architectures, even if size_t and uintptr_t are of different length. Adjustments may be needed for CHERI though. A man page is provided, too. No unit test for now. Reviewed by: kib, imp, ziaee (manpages), pauamma@gundo.com Approved by: markj (mentor) MFC after: 1 month Relnotes: yes Differential Revision: https://reviews.freebsd.org/D53673 (cherry picked from commit 6c57e368eb1777f6097158eeca2fcc175d068dba)
53 lines
1.1 KiB
Groff
53 lines
1.1 KiB
Groff
.\"
|
|
.\" Copyright (c) 2025 Robert Clausecker <fuz@FreeBSD.org>
|
|
.\"
|
|
.\" SPDX-License-Identifier: BSD-2-Clause
|
|
.\"
|
|
.Dd November 10, 2025
|
|
.Dt MEMALIGNMENT 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm memalignment
|
|
.Nd find the memory alignment of an object
|
|
.Sh SYNOPSIS
|
|
.Lb libc
|
|
.In stdlib.h
|
|
.Ft size_t
|
|
.Fn memalignment "const void *ptr"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn memalignment
|
|
function determines the alignment of the object pointed to by
|
|
.Fa ptr .
|
|
This alignment is a power of\~2, and may be larger than the range
|
|
supported by the
|
|
.Sy alignof
|
|
operator.
|
|
The value returned can be compared to the result of
|
|
.Sy alignof ,
|
|
and if it is greater or equal, the alignment requirement of the operand
|
|
is satisfied.
|
|
.Sh RETURN VALUES
|
|
Returns the alignment of
|
|
.Fa ptr
|
|
as a power of\~2.
|
|
If
|
|
.Fa ptr
|
|
is a null pointer, an alignment of zero is returned.
|
|
An alignment of zero indicates that the tested pointer cannot be used to
|
|
access an object of any type.
|
|
.Sh SEE ALSO
|
|
.Xr aligned_alloc 3 ,
|
|
.Xr posix_memalign 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn memalignment
|
|
function conforms to
|
|
.St -isoC-2023 .
|
|
.Sh HISTORY
|
|
The
|
|
.Fn memalignment
|
|
function was added in
|
|
.Fx 15.1.
|
|
.Sh AUTHOR
|
|
.An Robert Clausecker Aq Mt fuz@FreeBSD.org
|