xref: /freebsd/contrib/ofed/opensm/include/complib/cl_packon.h (revision 87181516ef48be852d5e5fee53c6e0dbfc62f21e)
1*d6b92ffaSHans Petter Selasky /*
2*d6b92ffaSHans Petter Selasky  * Copyright (c) 2004, 2005 Voltaire, Inc. All rights reserved.
3*d6b92ffaSHans Petter Selasky  * Copyright (c) 2002-2005 Mellanox Technologies LTD. All rights reserved.
4*d6b92ffaSHans Petter Selasky  * Copyright (c) 1996-2003 Intel Corporation. All rights reserved.
5*d6b92ffaSHans Petter Selasky  *
6*d6b92ffaSHans Petter Selasky  * This software is available to you under a choice of one of two
7*d6b92ffaSHans Petter Selasky  * licenses.  You may choose to be licensed under the terms of the GNU
8*d6b92ffaSHans Petter Selasky  * General Public License (GPL) Version 2, available from the file
9*d6b92ffaSHans Petter Selasky  * COPYING in the main directory of this source tree, or the
10*d6b92ffaSHans Petter Selasky  * OpenIB.org BSD license below:
11*d6b92ffaSHans Petter Selasky  *
12*d6b92ffaSHans Petter Selasky  *     Redistribution and use in source and binary forms, with or
13*d6b92ffaSHans Petter Selasky  *     without modification, are permitted provided that the following
14*d6b92ffaSHans Petter Selasky  *     conditions are met:
15*d6b92ffaSHans Petter Selasky  *
16*d6b92ffaSHans Petter Selasky  *      - Redistributions of source code must retain the above
17*d6b92ffaSHans Petter Selasky  *        copyright notice, this list of conditions and the following
18*d6b92ffaSHans Petter Selasky  *        disclaimer.
19*d6b92ffaSHans Petter Selasky  *
20*d6b92ffaSHans Petter Selasky  *      - Redistributions in binary form must reproduce the above
21*d6b92ffaSHans Petter Selasky  *        copyright notice, this list of conditions and the following
22*d6b92ffaSHans Petter Selasky  *        disclaimer in the documentation and/or other materials
23*d6b92ffaSHans Petter Selasky  *        provided with the distribution.
24*d6b92ffaSHans Petter Selasky  *
25*d6b92ffaSHans Petter Selasky  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
26*d6b92ffaSHans Petter Selasky  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
27*d6b92ffaSHans Petter Selasky  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
28*d6b92ffaSHans Petter Selasky  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
29*d6b92ffaSHans Petter Selasky  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
30*d6b92ffaSHans Petter Selasky  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
31*d6b92ffaSHans Petter Selasky  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
32*d6b92ffaSHans Petter Selasky  * SOFTWARE.
33*d6b92ffaSHans Petter Selasky  *
34*d6b92ffaSHans Petter Selasky  */
35*d6b92ffaSHans Petter Selasky 
36*d6b92ffaSHans Petter Selasky /*
37*d6b92ffaSHans Petter Selasky  * Abstract:
38*d6b92ffaSHans Petter Selasky  *  Turns on byte packing, which is necessary for passing information from
39*d6b92ffaSHans Petter Selasky  *	system to system over a network to ensure no padding by the compiler has
40*d6b92ffaSHans Petter Selasky  *	taken place.
41*d6b92ffaSHans Petter Selasky  */
42*d6b92ffaSHans Petter Selasky 
43*d6b92ffaSHans Petter Selasky /****h* Component Library/Structure Packing
44*d6b92ffaSHans Petter Selasky * NAME
45*d6b92ffaSHans Petter Selasky *	Structure Packing
46*d6b92ffaSHans Petter Selasky *
47*d6b92ffaSHans Petter Selasky * DESCRIPTION
48*d6b92ffaSHans Petter Selasky *	The structure packing header files allow packing structures on byte
49*d6b92ffaSHans Petter Selasky *	boundaries.
50*d6b92ffaSHans Petter Selasky *
51*d6b92ffaSHans Petter Selasky *	Structure packing should be used whenever a structure is transmitted
52*d6b92ffaSHans Petter Selasky *	between systems, as different platforms pad structures differently if
53*d6b92ffaSHans Petter Selasky *	they are not packed.  Packing a structure that is not transmitted between
54*d6b92ffaSHans Petter Selasky *	systems can be detrimental to performance, as fields in the structure may
55*d6b92ffaSHans Petter Selasky *	not align properly for some platforms. Care must be taken when creating
56*d6b92ffaSHans Petter Selasky *	packed structures that the alignment rules for all platforms are followed.
57*d6b92ffaSHans Petter Selasky *
58*d6b92ffaSHans Petter Selasky *	To pack a structure, include cl_packon.h before defining the structure, and
59*d6b92ffaSHans Petter Selasky *	include cl_packoff.h after the structure definition.  Multiple structures
60*d6b92ffaSHans Petter Selasky *	can be packed between the two include statements if desired.
61*d6b92ffaSHans Petter Selasky *
62*d6b92ffaSHans Petter Selasky *	The structure definition itself must use the PACK_SUFFIX keyword.
63*d6b92ffaSHans Petter Selasky *
64*d6b92ffaSHans Petter Selasky * EXAMPLE
65*d6b92ffaSHans Petter Selasky *	#include <complib/cl_packon.h>
66*d6b92ffaSHans Petter Selasky *
67*d6b92ffaSHans Petter Selasky *	typedef _my_struct_t
68*d6b92ffaSHans Petter Selasky *	{
69*d6b92ffaSHans Petter Selasky *	    uint64 large;
70*d6b92ffaSHans Petter Selasky *	    uint32 medium;
71*d6b92ffaSHans Petter Selasky *	    uint16 small;
72*d6b92ffaSHans Petter Selasky *
73*d6b92ffaSHans Petter Selasky *	} PACK_SUFFIX my_struct_t;
74*d6b92ffaSHans Petter Selasky *	#include <complib/cl_packoff.h>
75*d6b92ffaSHans Petter Selasky *********/
76*d6b92ffaSHans Petter Selasky 
77*d6b92ffaSHans Petter Selasky #ifndef PACK_SUFFIX
78*d6b92ffaSHans Petter Selasky #define PACK_SUFFIX __attribute__((packed))
79*d6b92ffaSHans Petter Selasky #endif
80*d6b92ffaSHans Petter Selasky 
81*d6b92ffaSHans Petter Selasky #ifdef _MSC_VER
82*d6b92ffaSHans Petter Selasky #pragma pack (push, 1)
83*d6b92ffaSHans Petter Selasky #endif
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