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Revision 1.3, Sat Nov 7 18:47:26 2015 UTC (4 years, 1 month ago) by wiz
Branch: MAIN
CVS Tags: prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-base, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, perseant-stdc-iso10646-base, perseant-stdc-iso10646, netbsd-8-base, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, netbsd-8, matt-nb8-mediatek-base, matt-nb8-mediatek, localcount-20160914, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan
Branch point for: phil-wifi, pgoyette-compat
Changes since 1.2: +5 -3 lines

Use Dv for NULL.

.\"	$NetBSD: posix_memalign.3,v 1.3 2015/11/07 18:47:26 wiz Exp $
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.\" FreeBSD: src/lib/libc/stdlib/posix_memalign.3,v 1.3 2007/03/28 04:32:51 jasone Exp
.\"
.Dd October 30, 2015
.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 and
.Fa size
must be a integer multiple of
.Fa alignment .
.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-2011 .