1#ifndef BOOST_SERIALIZATION_FORCE_INCLUDE_HPP
2#define BOOST_SERIALIZATION_FORCE_INCLUDE_HPP
3
4// MS compatible compilers support #pragma once
5#if defined(_MSC_VER)
6# pragma once
7#endif
8
9/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
10// force_include.hpp:
11
12// (C) Copyright 2002 Robert Ramey - http://www.rrsd.com .
13// Use, modification and distribution is subject to the Boost Software
14// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
15// http://www.boost.org/LICENSE_1_0.txt)
16
17// See http://www.boost.org for updates, documentation, and revision history.
18
19#include <boost/config.hpp>
20
21// the following help macro is to guarentee that certain coded
22// is not removed by over-eager linker optimiser. In certain cases
23// we create static objects must be created but are actually never
24// referenced - creation has a side-effect such as global registration
25// which is important to us. We make an effort to refer these objects
26// so that a smart linker won't remove them as being unreferenced.
27// In microsoft compilers, inlining the code that does the referring
28// means the code gets lost and the static object is not included
29// in the library and hence never registered. This manifests itself
30// in an ungraceful crash at runtime when (and only when) built in
31// release mode.
32
33#if defined(BOOST_HAS_DECLSPEC) && !defined(__COMO__)
34# define BOOST_DLLEXPORT __declspec(dllexport)
35#elif ! defined(_WIN32) && ! defined(_WIN64)
36# if defined(__MWERKS__)
37# define BOOST_DLLEXPORT __declspec(dllexport)
38# elif defined(__GNUC__) && (__GNUC__ >= 3)
39# define BOOST_USED __attribute__ ((__used__))
40# elif defined(__IBMCPP__) && (__IBMCPP__ >= 1110)
41# define BOOST_USED __attribute__ ((__used__))
42# elif defined(__INTEL_COMPILER) && (BOOST_INTEL_CXX_VERSION >= 800)
43# define BOOST_USED __attribute__ ((__used__))
44# endif
45#endif
46
47#ifndef BOOST_USED
48# define BOOST_USED
49#endif
50
51#ifndef BOOST_DLLEXPORT
52# define BOOST_DLLEXPORT
53#endif
54
55#endif // BOOST_SERIALIZATION_FORCE_INCLUDE_HPP
56

source code of include/boost/serialization/force_include.hpp