fe9bbf72d9
Since aligned_alloc does not demand that size is to be multiple of alignment anymore, don't make that claim in the man page.
134 lines
3.6 KiB
Groff
134 lines
3.6 KiB
Groff
.\" $NetBSD: posix_memalign.3,v 1.7 2019/12/06 16:19:32 nros Exp $
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.\"
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.\" Copyright (C) 2006 Jason Evans <jasone@FreeBSD.org>.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), this list of conditions and the following disclaimer in
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.\" the documentation and/or other materials provided with the
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.\" distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
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.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" FreeBSD: src/lib/libc/stdlib/posix_memalign.3,v 1.3 2007/03/28 04:32:51 jasone Exp
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.\"
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.Dd July 27, 2018
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.Dt POSIX_MEMALIGN 3
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.Os
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.Sh NAME
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.Nm posix_memalign , aligned_alloc
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.Nd aligned memory allocation
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdlib.h
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.Ft int
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.Fn posix_memalign "void **ptr" "size_t alignment" "size_t size"
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.Ft void *
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.Fn aligned_alloc "size_t alignment" "size_t size"
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.Sh DESCRIPTION
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The
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.Fn posix_memalign
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function allocates
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.Fa size
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bytes of memory such that the allocation's base address is an even multiple of
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.Fa alignment ,
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and returns the allocation in the value pointed to by
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.Fa ptr .
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The requested
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.Fa alignment
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must be a power of 2 at least as large as
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.Fn sizeof "void *" .
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.Pp
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The
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.Fn aligned_alloc
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function allocates
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.Fa size
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bytes of memory such that the allocation's base address is an even multiple of
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.Fa alignment .
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The requested
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.Fa alignment
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must be a power of 2.
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.Pp
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Memory that is allocated via
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.Fn posix_memalign
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or
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.Fn aligned_alloc
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can be used as an argument in subsequent calls to
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.Xr realloc 3
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and
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.Xr free 3 .
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.Sh RETURN VALUES
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The
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.Fn posix_memalign
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function returns the value 0 if successful; otherwise it returns an error value.
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.Pp
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The
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.Fn aligned_alloc
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function returns a pointer to the allocated memory if successful; on failure it
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returns
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.Dv NULL
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and sets
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.Fa errno
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to indicate the error.
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.Sh ERRORS
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The
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.Fn posix_memalign
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and
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.Fn aligned_alloc
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functions will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The
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.Fa alignment
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parameter is not a power of 2.
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.It Bq Er ENOMEM
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Memory allocation error.
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.El
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.Pp
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The
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.Fn posix_memalign
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function will also fail if
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The
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.Fa alignment
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parameter is not at least as large as
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.Fn sizeof "void *" .
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.El
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.Sh SEE ALSO
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.Xr free 3 ,
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.Xr malloc 3 ,
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.Xr realloc 3 ,
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.Xr valloc 3
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.Sh STANDARDS
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The
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.Fn posix_memalign
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function conforms to
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.St -p1003.1-2001 .
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The
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.Fn aligned_alloc
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function conforms to
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.St -isoC-2018 .
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.Sh HISTORY
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.St -isoC-2011
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required size to be an integer multiple of alignment.
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This requirement was removed in later standards.
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