145 lines
3.7 KiB
Groff
145 lines
3.7 KiB
Groff
.\" $NetBSD: posix_memalign.3,v 1.6 2018/07/27 15:15:30 maya Exp $
|
|
.\"
|
|
.\" Copyright (C) 2006 Jason Evans <jasone@FreeBSD.org>.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice(s), this list of conditions and the following disclaimer as
|
|
.\" the first lines of this file unmodified other than the possible
|
|
.\" addition of one or more copyright notices.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice(s), this list of conditions and the following disclaimer in
|
|
.\" the documentation and/or other materials provided with the
|
|
.\" distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
|
|
.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
|
|
.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
|
|
.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
|
.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
|
|
.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
|
|
.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" FreeBSD: src/lib/libc/stdlib/posix_memalign.3,v 1.3 2007/03/28 04:32:51 jasone Exp
|
|
.\"
|
|
.Dd July 27, 2018
|
|
.Dt POSIX_MEMALIGN 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm posix_memalign , aligned_alloc
|
|
.Nd aligned memory allocation
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In stdlib.h
|
|
.Ft int
|
|
.Fn posix_memalign "void **ptr" "size_t alignment" "size_t size"
|
|
.Ft void *
|
|
.Fn aligned_alloc "size_t alignment" "size_t size"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn posix_memalign
|
|
function allocates
|
|
.Fa size
|
|
bytes of memory such that the allocation's base address is an even multiple of
|
|
.Fa alignment ,
|
|
and returns the allocation in the value pointed to by
|
|
.Fa ptr .
|
|
The requested
|
|
.Fa alignment
|
|
must be a power of 2 at least as large as
|
|
.Fn sizeof "void *" .
|
|
.Pp
|
|
The
|
|
.Fn aligned_alloc
|
|
function allocates
|
|
.Fa size
|
|
bytes of memory such that the allocation's base address is an even multiple of
|
|
.Fa alignment .
|
|
The requested
|
|
.Fa alignment
|
|
must be a power of 2.
|
|
.Pp
|
|
Memory that is allocated via
|
|
.Fn posix_memalign
|
|
or
|
|
.Fn aligned_alloc
|
|
can be used as an argument in subsequent calls to
|
|
.Xr realloc 3
|
|
and
|
|
.Xr free 3 .
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn posix_memalign
|
|
function returns the value 0 if successful; otherwise it returns an error value.
|
|
.Pp
|
|
The
|
|
.Fn aligned_alloc
|
|
function returns a pointer to the allocated memory if successful; on failure it
|
|
returns
|
|
.Dv NULL
|
|
and sets
|
|
.Fa errno
|
|
to indicate the error.
|
|
.Sh ERRORS
|
|
The
|
|
.Fn posix_memalign
|
|
and
|
|
.Fn aligned_alloc
|
|
functions will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa alignment
|
|
parameter is not a power of 2.
|
|
.It Bq Er ENOMEM
|
|
Memory allocation error.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn posix_memalign
|
|
function will also fail if
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa alignment
|
|
parameter is not at least as large as
|
|
.Fn sizeof "void *" .
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn aligned_alloc
|
|
function will also fail if
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa size
|
|
parameter is not an integer multiple of
|
|
.Fa alignment .
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr free 3 ,
|
|
.Xr malloc 3 ,
|
|
.Xr realloc 3 ,
|
|
.Xr valloc 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn posix_memalign
|
|
function conforms to
|
|
.St -p1003.1-2001 .
|
|
The
|
|
.Fn aligned_alloc
|
|
function conforms to
|
|
.St -isoC-2018 .
|
|
.Sh HISTORY
|
|
.St -isoC-2011
|
|
required size to be an integer multiple of alignment.
|
|
This requirement was removed in later standards.
|