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我正在将我的一些 Linux 程序移植到 Windows。我想确保我的代码可以同时使用 MinGW 和 Visual C++ 10 进行编译，而不需要太多#define魔法#ifdef。我已经设法解决了大多数问题，除了这个。我有一个类似于以下的代码，它可以用 g++ 4.6.3 编译，但不能用 Visual C++ 10：

#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;
}

我什至无法理解编译器的输出：

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() 但我不知道代码到底出了什么问题（因为它编译得很好，没有一个 g++ 警告）。任何人都知道如何在不求助于前身魔法的情况下修复我的代码？

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2 回答 2

2

添加typedef BaseT result_type;到 的定义中fopow。前几天需要的模板黑客在decltype试图弄清楚返回类型fopow::operator()是什么时迷路了。（而且，是的，你是对的：它在通话中迷路了bind()；特别是第一个。）

或者，如果您愿意，可以使用@ecatmur 建议的修复方法：派生自std::binary_function<BaseT, ExpT, BaseT>. 这也将添加result_type到模板中，以及first_argument_type和second_argument_type。bind不需要参数类型。

于 2012-09-11T17:33:27.760 回答
2

std::bind不是您在 VS2010 中认为的那样：它实际上是std::tr1::bind, 和 uses std::tr1::result_of，它远不如std::result_ofC++11 标准规定的编译器辅助功能强大。

特别是，不要尝试std::bind在 VS10 中使用 lambda 表达式。

fopow您可以通过继承来解决此问题std::binary_function<BaseT, ExpT, BaseT>。

于 2012-09-11T17:35:12.270 回答