以下在Visual Studio 08中编译正常，但是当我升级到Visual Studio 10时，它不再编译。我不知道究竟是什么导致了这一点，因为错误（至少对我来说）不是很有帮助。这是一个大项目，所以我在一个小的测试用例中发生了同样的错误，如下所示。有什么想法吗？
MyHash.h
#ifndef __MyHash_h__
#define __MyHash_h__
#include <string>
#include <tuple>
#include <hash_map>
#include <boost/functional/hash.hpp>
typedef std::tr1::tuple<std::string, unsigned int, std::string> Identifier;
class ValueNode {
public:
ValueNode() { str = "TEST"; }
virtual ~ValueNode() { }
std::string getStr() { return str; }
private:
std::string str;
};
template<> inline
size_t stdext::hash_value<Identifier>(Identifier const& id)
{
size_t seed = 0xffff0000;
boost::hash_combine(seed, std::tr1::get<0>(id));
boost::hash_combine(seed, std::tr1::get<1>(id));
boost::hash_combine(seed, std::tr1::get<2>(id));
return seed;
}
class HashMapClass {
private:
typedef stdext::hash_map<Identifier, ValueNode> MyMap;
public:
HashMapClass() { }
virtual ~HashMapClass() { }
void meshAround();
private:
MyMap mMap;
};
#endif // __MyHash_h__
Main.cpp的：
#include "MyHash.h"
void HashMapClass::meshAround() {
ValueNode test;
Identifier id("HEYY", 140, "THERE");
mMap[id] = test;
}
int main() {
std::cout << "HEY" << std::endl;
HashMapClass hash1;
hash1.meshAround();
std::cout << "EXIT" << std::endl;
return 0;
}
错误：
1>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\tuple(127): error C2664: 'std::basic_string<_Elem,_Traits,_Ax>::basic_string(const std::basic_string<_Elem,_Traits,_Ax> &)' : cannot convert parameter 1 from 'const Identifier' to 'const std::basic_string<_Elem,_Traits,_Ax> &'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>,
1> _Ax=std::allocator<char>
1> ]
1> Reason: cannot convert from 'const Identifier' to 'const std::basic_string<_Elem,_Traits,_Ax>'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>,
1> _Ax=std::allocator<char>
1> ]
1> No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
1> c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xxtuple0(9) : see reference to function template instantiation 'std::tr1::_Cons_node<_Car,_Cdr>::_Cons_node<_Ty,std::tr1::_Nil&,std::tr1::_Nil&,std::tr1::_Nil&,std::tr1::_Nil&,std::tr1::_Nil&,std::tr1::_Nil&,std::tr1::_Nil&,std::tr1::_Nil&,std::tr1::_Nil&>(_Farg0 &&,_Farg1,_Farg2,_Farg3,_Farg4,_Farg5,_Farg6,_Farg7,_Farg8,_Farg9)' being compiled
1> with
1> [
1> _Car=std::string,
1> _Cdr=std::tr1::_Cons_node<unsigned int,std::tr1::_Cons_node<std::string,std::tr1::_Tuple_type<std::tr1::_Nil,std::tr1::_Nil,std::tr1::_Nil,std::tr1::_Nil,std::tr1::_Nil,std::tr1::_Nil,std::tr1::_Nil,std::tr1::_Nil,std::tr1::_Nil,std::tr1::_Nil>::_Type>>,
1> _Ty=Identifier,
1> _Farg0=Identifier,
1> _Farg1=std::tr1::_Nil &,
1> _Farg2=std::tr1::_Nil &,
1> _Farg3=std::tr1::_Nil &,
1> _Farg4=std::tr1::_Nil &,
1> _Farg5=std::tr1::_Nil &,
1> _Farg6=std::tr1::_Nil &,
1> _Farg7=std::tr1::_Nil &,
1> _Farg8=std::tr1::_Nil &,
1> _Farg9=std::tr1::_Nil &
1> ]
1> c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\utility(145) : see reference to function template instantiation 'std::tr1::tuple<_Arg0,_Arg1,_Arg2>::tuple<const std::tr1::tuple<_Arg0,_Arg1,_Arg2>>(_Farg0 &&)' being compiled
1> with
1> [
1> _Arg0=std::string,
1> _Arg1=unsigned int,
1> _Arg2=std::string,
1> _Farg0=const std::tr1::tuple<std::string,unsigned int,std::string>
1> ]
1> c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\utility(142) : while compiling class template member function 'std::_Pair_base<_Ty1,_Ty2>::_Pair_base(const std::tr1::tuple<_Arg0,_Arg1,_Arg2> &&,ValueNode &&)'
1> with
1> [
1> _Ty1=const Identifier,
1> _Ty2=ValueNode,
1> _Arg0=std::string,
1> _Arg1=unsigned int,
1> _Arg2=std::string
1> ]
1> c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\utility(174) : see reference to class template instantiation 'std::_Pair_base<_Ty1,_Ty2>' being compiled
1> with
1> [
1> _Ty1=const Identifier,
1> _Ty2=ValueNode
1> ]
1> c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\hash_map(206) : see reference to class template instantiation 'std::pair<_Ty1,_Ty2>' being compiled
1> with
1> [
1> _Ty1=const Identifier,
1> _Ty2=ValueNode
1> ]
1> c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\hash_map(203) : while compiling class template member function 'ValueNode &stdext::hash_map<_Kty,_Ty>::operator [](const std::tr1::tuple<_Arg0,_Arg1,_Arg2> &)'
1> with
1> [
1> _Kty=Identifier,
1> _Ty=ValueNode,
1> _Arg0=std::string,
1> _Arg1=unsigned int,
1> _Arg2=std::string
1> ]
1> c:\-----------------------\MyHash.h(41) : see reference to class template instantiation 'stdext::hash_map<_Kty,_Ty>' being compiled
1> with
1> [
1> _Kty=Identifier,
1> _Ty=ValueNode
1> ]
答案 0 :(得分：1)
根据上面的评论，这看起来是VC 2010中的一个错误。（placing objects deriving from tuple into a vector in C++）我已经从使用元组切换到小类，错误就消失了。为了完整起见，这是新课程：
class Identifier {
public:
Identifier(std::string a1, unsigned int a2, std::string a3) : arg1(a1), arg2(a2), arg3(a3) { }
std::string getArg1() const { return arg1; }
unsigned int getArg2() const { return arg2; }
std::string getArg3() const { return arg3; }
private:
std::string arg1;
unsigned int arg2;
std::string arg3;
};
inline bool operator< (const Identifier& lhs, const Identifier& rhs) {
return (lhs.getArg1() < rhs.getArg1() && lhs.getArg2() < rhs.getArg2() && lhs.getArg3() < rhs.getArg3());
}