[apple/libc.git] / gen / malloc_size.3

.\" Copyright (c) 2006 Apple Computer, Inc.  All rights reserved.
.\"
.\" @APPLE_LICENSE_HEADER_START@
.\"
.\" The contents of this file constitute Original Code as defined in and
.\" are subject to the Apple Public Source License Version 1.1 (the
.\" "License").  You may not use this file except in compliance with the
.\" License.  Please obtain a copy of the License at
.\" http://www.apple.com/publicsource and read it before using this file.
.\"
.\" This Original Code and all software distributed under the License are
.\" distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
.\" EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
.\" INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
.\" FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
.\" License for the specific language governing rights and limitations
.\" under the License.
.\"
.\" @APPLE_LICENSE_HEADER_END@
.\"
.Dd May 23, 2006
.Dt MALLOC_SIZE 3
.Os
.Sh NAME
.Nm malloc_good_size ,
.Nm malloc_size
.Nd memory allocation information
.Sh SYNOPSIS
.In malloc/malloc.h
.Ft size_t
.Fo malloc_good_size
.Fa "size_t size"
.Fc
.Ft size_t
.Fo malloc_size
.Fa "const void *ptr"
.Fc
.Sh DESCRIPTION
The
.Fn malloc_size
function returns the size of the memory block
that backs the allocation pointed to by
.Fa ptr .
The memory block size is always at least as large
as the allocation it backs, and may be larger.
.Pp
The
.Fn malloc_good_size
function rounds
.Fa size
up to a value that the allocator implementation can allocate
without adding any padding;
it then returns that rounded-up value.
.Sh SEE ALSO
.Xr malloc 3
Commit	Line	Data
224c7076 A	1	.\" Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
	2	.\"
	3	.\" @APPLE_LICENSE_HEADER_START@
	4	.\"
	5	.\" The contents of this file constitute Original Code as defined in and
	6	.\" are subject to the Apple Public Source License Version 1.1 (the
	7	.\" "License"). You may not use this file except in compliance with the
	8	.\" License. Please obtain a copy of the License at
	9	.\" http://www.apple.com/publicsource and read it before using this file.
	10	.\"
	11	.\" This Original Code and all software distributed under the License are
	12	.\" distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	13	.\" EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	14	.\" INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	15	.\" FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	16	.\" License for the specific language governing rights and limitations
	17	.\" under the License.
	18	.\"
	19	.\" @APPLE_LICENSE_HEADER_END@
	20	.\"
	21	.Dd May 23, 2006
	22	.Dt MALLOC_SIZE 3
	23	.Os
	24	.Sh NAME
	25	.Nm malloc_good_size ,
	26	.Nm malloc_size
	27	.Nd memory allocation information
	28	.Sh SYNOPSIS
	29	.In malloc/malloc.h
	30	.Ft size_t
	31	.Fo malloc_good_size
	32	.Fa "size_t size"
	33	.Fc
	34	.Ft size_t
	35	.Fo malloc_size
	36	.Fa "const void *ptr"
	37	.Fc
	38	.Sh DESCRIPTION
	39	The
	40	.Fn malloc_size
	41	function returns the size of the memory block
	42	that backs the allocation pointed to by
	43	.Fa ptr .
	44	The memory block size is always at least as large
	45	as the allocation it backs, and may be larger.
	46	.Pp
	47	The
	48	.Fn malloc_good_size
	49	function rounds
	50	.Fa size
	51	up to a value that the allocator implementation can allocate
	52	without adding any padding;
	53	it then returns that rounded-up value.
	54	.Sh SEE ALSO
	55	.Xr malloc 3