我正在将一些Linux程序移植到Windows。我想确保我的代码使用MinGW和Visual C ++ 10进行编译，而没有太多#define和#ifdef魔法。除了这个问题，我已经设法解决了大部分问题。我有一个类似于以下的代码，它与g ++ 4.6.3编译良好，但与Visual C ++ 10不兼容：
#include <iostream>
#include <vector>
#include <array>
#include <algorithm>
#include <functional>
#include <cmath>
#include <iterator>
typedef unsigned char UINT8;
const UINT8 MAX_COLL = 10;
template< typename BaseT, typename ExpT >
struct fopow {
BaseT operator() ( BaseT base, ExpT exp ) const {
return std::pow( base, exp );
}
};
int main() {
using namespace std;
using namespace std::placeholders;
array<int, MAX_COLL> intCollection_init = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
vector<int> intCollection( intCollection_init.begin(), intCollection_init.end() );
transform( intCollection.begin(), intCollection.end(),
ostream_iterator<int>( cout, " " ),
bind( fopow<int, int>(), 3, _1 )
);
cout << endl;
transform( intCollection.begin(), intCollection.end(),
ostream_iterator<int>( cout, " " ),
bind( fopow<int, int>(), _1, 3 )
);
cout << endl;
}
编译器输出对我来说甚至无法理解：
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.00.40219.01 for 80x86
Copyright (C) Microsoft Corporation. All rights reserved.
Test2.cpp C:\Program Files\Microsoft Visual Studio
10.0\VC\INCLUDE\xxresult(28) : error C2903: 'result' : symbol is neither a class template nor a function template
C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(40) : see reference to class tem plate instantiation 'std::tr1::_Result_type2<__formal,_Fty,_Arg0,_Arg1>' being compiled
with
[
__formal=false,
_Fty=fopow<int,int>,
_Arg0=std::tr1::_Nil &,
_Arg1=std::tr1::_Nil &
]
C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(597) : see reference to class te mplate instantiation 'std::tr1::_Result_of2<_Fty,_Farg0,_Farg1>' being compiled
with
[
_Fty=fopow<int,int>,
_Farg0=std::tr1::_Nil &,
_Farg1=std::tr1::_Nil &
]
C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xrefwrap(28) : see reference to class tem plate instantiation 'std::tr1::_Result_of<_Ty>' being compiled
with
[
_Ty=fopow<int,int> (std::tr1::_Nil &,std::tr1::_Nil &)
]
C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxbind1(273) : see reference to class tem plate instantiation 'std::tr1::result_of<_Fty>' being compiled
with
[
_Fty=fopow<int,int> (std::tr1::_Nil &,std::tr1::_Nil &)
]
C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxbind0(10) : see reference to class temp late instantiation 'std::tr1::_Bind2<_Callable,_Arg0,_Arg1>::_Return<_Barg0,_Barg1,_Barg2,_Barg3,_Barg4,_B arg5,_Barg6,_Barg7,_Barg8,_Barg9>' being compiled
with
[
_Callable=std::tr1::_Callable_obj<fopow<int,int>,false>,
_Arg0=int,
_Arg1=std::tr1::_Ph<1>,
_Barg0=std::tr1::_Nil &,
_Barg1=std::tr1::_Nil &,
_Barg2=std::tr1::_Nil &,
_Barg3=std::tr1::_Nil &,
_Barg4=std::tr1::_Nil &,
_Barg5=std::tr1::_Nil &,
_Barg6=std::tr1::_Nil &,
_Barg7=std::tr1::_Nil &,
_Barg8=std::tr1::_Nil &,
_Barg9=std::tr1::_Nil &
]
C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\functional(408) : see reference to class template instantiation 'std::tr1::_Bind_base<_Ret,_BindN>' being compiled
with
[
_Ret=std::tr1::_Notforced,
_BindN=std::tr1::_Bind2<std::tr1::_Callable_obj<fopow<int,int>,false>,int,std::tr1::_Ph<1>>
]
Test2.cpp(26) : see reference to class template instantiation 'std::tr1::_Bind_fty<_Fty,_Ret,_Bind N>' being compiled
with
[
_Fty=fopow<int,int>,
_Ret=std::tr1::_Notforced,
_BindN=std::tr1::_Bind2<std::tr1::_Callable_obj<fopow<int,int>,false>,int,std::tr1::_Ph<1>>
] C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(28) : error C2039: 'result' : is not a m ember of 'fopow<BaseT,ExpT>'
with
[
BaseT=int,
ExpT=int
] C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(28) : error C2143: syntax error : missin g ';' before '<' C:\Program Files\Microsoft Visual Studio
10.0\VC\INCLUDE\xxresult(28) : error C4430: missing type specifie r - int assumed. Note: C++ does not support default-int C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(28) : error C2039: 'type' : is not a mem ber of '`global namespace'' C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(28) : error C2238: unexpected token(s) p receding ';' C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(40) : error C2039: '_Type' : is not a me mber of 'std::tr1::_Result_type2<__formal,_Fty,_Arg0,_Arg1>'
with
[
__formal=false,
_Fty=fopow<int,int>,
_Arg0=std::tr1::_Nil &,
_Arg1=std::tr1::_Nil &
] C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(40) : error C2146: syntax error : missin g ';' before identifier '_Type' C:\Program Files\Microsoft Visual Studio
10.0\VC\INCLUDE\xxresult(40) : error C4430: missing type specifie r - int assumed. Note: C++ does not support default-int C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(40) : error C2602: 'std::tr1::_Result_of 2<_Fty,_Farg0,_Farg1>::_Type' is not a member of a base class of 'std::tr1::_Result_of2<_Fty,_Farg0,_Farg1
>'
with
[
_Fty=fopow<int,int>,
_Farg0=std::tr1::_Nil &,
_Farg1=std::tr1::_Nil &
]
C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(40) : see declaration of 'std::t r1::_Result_of2<_Fty,_Farg0,_Farg1>::_Type'
with
[
_Fty=fopow<int,int>,
_Farg0=std::tr1::_Nil &,
_Farg1=std::tr1::_Nil &
] C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxresult(40) : error C2868: 'std::tr1::_Result_of 2<_Fty,_Farg0,_Farg1>::_Type' : illegal syntax for using-declaration; expected qualified-name
with
[
_Fty=fopow<int,int>,
_Farg0=std::tr1::_Nil &,
_Farg1=std::tr1::_Nil &
]
我认为问题的根源是bind（）或transform（）但是我不知道代码究竟出了什么问题（因为它编译得很好没有g ++的单一警告）。任何人都知道如何在不诉诸预处理魔法的情况下修复我的代码？
答案 0 :(得分：2)
将typedef BaseT result_type;添加到fopow的定义中。 decltype之前几天所需的模板hackery正在迷失，试图找出fopow::operator()的返回类型。 （而且，是的，你是对的：它在bind()电话中迷失了;特别是第一个电话。）
或者，如果您愿意，可以使用@ecatmur建议的修复：从std::binary_function<BaseT, ExpT, BaseT>派生。这也会为模板添加result_type，以及first_argument_type和second_argument_type。 bind不需要参数类型。
答案 1 :(得分：2)
std::bind不是你在VS2010中的想法：它实际上是std::tr1::bind，而是使用std::tr1::result_of，它比编译器辅助std::result_of强大得多。由C ++ 11标准强制执行。
特别是，不要尝试在VS10中使用std::bind和lambda表达式。
您可以通过fopow继承std::binary_function<BaseT, ExpT, BaseT>来解决此问题。