1#ifndef BOOST_SERIALIZATION_PFTO_HPP
2#define BOOST_SERIALIZATION_PFTO_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// pfto.hpp: workarounds for compilers which have problems supporting
11// Partial Function Template Ordering (PFTO).
12
13// (C) Copyright 2002 Robert Ramey - http://www.rrsd.com .
14// Use, modification and distribution is subject to the Boost Software
15// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
16// http://www.boost.org/LICENSE_1_0.txt)
17
18// See http://www.boost.org/libs/serialization for updates, documentation, and revision history.
19// PFTO version is used to specify the last argument of certain functions
20// Function it is used to support compilers that fail to support correct Partial
21// Template Ordering
22#include <boost/config.hpp>
23
24// some compilers can use an exta argument and use function overloading
25// to choose desired function. This extra argument is long in the default
26// function implementation and int for the rest. The function is called
27// with an int argument. This first attempts to match functions with an
28// int argument before the default one (with a long argument). This is
29// known to function with VC 6.0. On other compilers this fails (Borland)
30// or causes other problems (GCC). note: this
31
32#if defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
33 #define BOOST_PFTO long
34#else
35 #define BOOST_PFTO
36#endif
37
38// here's another approach. Rather than use a default function - make sure
39// there is no default at all by requiring that all function invocations
40// have a "wrapped" argument type. This solves a problem with VC 6.0
41// (and perhaps others) while implementing templated constructors.
42
43namespace boost {
44namespace serialization {
45
46template<class T>
47struct pfto_wrapper {
48 const T & t;
49 operator const T & (){
50 return t;
51 }
52 pfto_wrapper (const T & rhs) : t(rhs) {}
53};
54
55template<class T>
56pfto_wrapper< T > make_pfto_wrapper(const T & t, BOOST_PFTO int){
57 return pfto_wrapper< T >(t);
58}
59
60template<class T>
61pfto_wrapper< T > make_pfto_wrapper(const pfto_wrapper< T > & t, int){
62 return t;
63}
64
65} // namespace serialization
66} // namespace boost
67
68#ifdef BOOST_NO_FUNCTION_TEMPLATE_ORDERING
69 #define BOOST_PFTO_WRAPPER(T) \
70 boost::serialization::pfto_wrapper< T >
71 #define BOOST_MAKE_PFTO_WRAPPER(t) \
72 boost::serialization::make_pfto_wrapper(t, 0)
73#else
74 #define BOOST_PFTO_WRAPPER(T) T
75 #define BOOST_MAKE_PFTO_WRAPPER(t) t
76#endif
77
78#endif // BOOST_SERIALIZATION_PFTO_HPP
79