在C++/CLI中使用unique_ptr時的鏈接器錯誤

Question

我目前正在將auto_ptr的實例轉換爲unique_ptr，但是我遇到了問題。它在代碼的C++部分很好用，但是當我在託管的C++/CLI層（該軟件同時使用C＃和C++）中執行時，會出現鏈接錯誤。它編譯好，但在鏈接時斷開。 auto_ptr從來沒有任何問題。

我目前正在使用Visual Studio 2010.有誰知道在C++/CLI中使用unique_ptr有任何問題嗎？

我試着在下面的一段代碼中總結我的問題，但請注意，下面的代碼實際上編譯和工作（我檢查指針的所有權被正確移動）。編譯時我沒有看到鏈接錯誤，但下面的代碼是純C++而不是C++/CLI。我只想有一個代碼如何構造的簡單例子，以便鏈接器錯誤更有意義。

#include "stdafx.h" 
#include <vector> 
#include <memory> 
#include <utility> 

using namespace std; 

namespace Test { 

template< class T > 
struct LinAlgPoint3 { 
    LinAlgPoint3() { x = y = z = 0; }; 

    union { 
    struct {T x,y,z;} ; 
    T data_[3]; 
    }; 
}; 

class ContainerClass 
{ 
public: 
    void setUniquePtr(
    unique_ptr< vector< LinAlgPoint3<float> > > newUniquePtr1 , 
    unique_ptr< vector< unsigned char > > newUniquePtr2) 
    { 
    m_uniquePtr1 = move(newUniquePtr1); 
    m_uniquePtr2 = move(newUniquePtr2); 
    } 

private: 
    unique_ptr< vector< LinAlgPoint3<float> > > m_uniquePtr1; 
    unique_ptr< vector< unsigned char > > m_uniquePtr2; 
}; 

int main(int argc, char** argv) 
{ 
    auto pos = unique_ptr< vector< LinAlgPoint3<float> > >(new vector< LinAlgPoint3<float> >()); 
    auto name = unique_ptr< vector< unsigned char > >(new vector< unsigned char >()); 
    ContainerClass container; 
    container.setUniquePtr(move(pos), move(name)); 
} 

} //namespace Test 

鏈接時，我得到的錯誤是：

error LNK2028: unresolved token (0A0018A5) "private: __cdecl std::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > >::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > >(class std::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > > const &)" (??0?$unique_ptr@V?$vector@U?$LinAlgPoint3@M@Test@@V?$allocator@U?$LinAlgPoint3@M@Test@@@std@@@std@@U?$default_delete@V?$vector@U?$LinAlgPoint3@M@Test@@V?$allocator@U?$LinAlgPoint3@M@Test@@@std@@@std@@@2@@std@@$$FAEAA@AEBV01@@Z) referenced in function "public: static void __clrcall std::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > >::<MarshalCopy>(class std::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > > *,class std::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > > *)" (?<MarshalCopy>@?$unique_ptr@V?$vector@U?$LinAlgPoint3@M@Test@@V?$allocator@U?$LinAlgPoint3@M@Test@@@std@@@std@@U?$default_delete@V?$vector@U?$LinAlgPoint3@M@Test@@V?$allocator@U?$LinAlgPoint3@M@Test@@@std@@@std@@@2@@std@@$$FSMXPEAV12@0@Z) 
1>TestClass.obj : error LNK2028: unresolved token (0A0018A6) "private: __cdecl std::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > >::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > >(class std::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > > const &)" (??0?$unique_ptr@V?$vector@EV?$allocator@E@std@@@std@@U?$default_delete@V?$vector@EV?$allocator@E@std@@@std@@@2@@std@@$$FAEAA@AEBV01@@Z) referenced in function "public: static void __clrcall std::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > >::<MarshalCopy>(class std::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > > *,class std::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > > *)" (?<MarshalCopy>@?$unique_ptr@V?$vector@EV?$allocator@E@std@@@std@@U?$default_delete@V?$vector@EV?$allocator@E@std@@@std@@@2@@std@@$$FSMXPEAV12@0@Z) 
1>TestClass.obj : error LNK2019: unresolved external symbol "private: __cdecl std::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > >::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > >(class std::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > > const &)" (??0?$unique_ptr@V?$vector@EV?$allocator@E@std@@@std@@U?$default_delete@V?$vector@EV?$allocator@E@std@@@std@@@2@@std@@$$FAEAA@AEBV01@@Z) referenced in function "public: static void __clrcall std::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > >::<MarshalCopy>(class std::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > > *,class std::unique_ptr<class std::vector<unsigned char,class std::allocator<unsigned char> >,struct std::default_delete<class std::vector<unsigned char,class std::allocator<unsigned char> > > > *)" (?<MarshalCopy>@?$unique_ptr@V?$vector@EV?$allocator@E@std@@@std@@U?$default_delete@V?$vector@EV?$allocator@E@std@@@std@@@2@@std@@$$FSMXPEAV12@0@Z) 
1>TestClass.obj : error LNK2019: unresolved external symbol "private: __cdecl std::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > >::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > >(class std::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > > const &)" (??0?$unique_ptr@V?$vector@U?$LinAlgPoint3@M@Test@@V?$allocator@U?$LinAlgPoint3@M@Test@@@std@@@std@@U?$default_delete@V?$vector@U?$LinAlgPoint3@M@Test@@V?$allocator@U?$LinAlgPoint3@M@Test@@@std@@@std@@@2@@std@@$$FAEAA@AEBV01@@Z) referenced in function "public: static void __clrcall std::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > >::<MarshalCopy>(class std::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > > *,class std::unique_ptr<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > >,struct std::default_delete<class std::vector<struct LinAlgPoint3<float>,class std::allocator<struct LinAlgPoint3<float> > > > > *)" (?<MarshalCopy>@?$unique_ptr@V?$vector@U?$LinAlgPoint3@M@Test@@V?$allocator@U?$LinAlgPoint3@M@Test@@@std@@@std@@U?$default_delete@V?$vector@U?$LinAlgPoint3@M@Test@@V?$allocator@U?$LinAlgPoint3@M@Test@@@std@@@std@@@2@@std@@$$FSMXPEAV12@0@Z) 
1>D:\Test\Test.dll : fatal error LNK1120: 4 unresolved externals 

正如你可以看到（如果你可以通過令人難以置信的可怕的消息得到）也有到MarshalCopy一些參考，這是令我擔心C++/CLI可能還不支持unique_ptr。

軟件的佈局

C# executable -> C++/CLI translation layer (dll) -> C++ dll 

所以C++的dll使用的unique_ptr編譯罰款，但C++/CLI DLL無法正常鏈接。

我忘記提及一些相當重要的事情：如果我使用unique_ptr更簡單的數據類型，例如一個字符串，它會成功鏈接。例如：

auto string1= unique_ptr<string>(new string(20000, 'S')); 
    auto string2 = unique_ptr<string>(new string(20000, 'A')); 
    string1= std::move(string2); 

，我也試着確保使用的變量，這樣編譯器不會優化它拿走。

編輯：我剛剛測試並稱接受unique_ptr<string>另一個外部功能，我試圖在上面string1發送和打破的！所以這個問題必須在生成的DLL之間，因爲std :: move（）在每個文件/類中運行良好。

Answer 1

嗯，不知道它現在有多相關，但是我和C++/CLI有完全相同的問題，並用r值引用代替值來解決它。我的意思是： 無效setUniquePtr（的unique_ptr & &一個，的unique_ptr & & B）

這樣，它編譯但它不是做事情最徹底的方法。

Answer 2

通讀這個複雜的錯誤信息，我認爲這是抱怨LinAlgPoint3結構沒有複製構造函數。嘗試實施複製構造函數，也許運營商=和==，看看是否修復它。

Answer 3

您不能在DLL之間傳遞C++對象，並期望它正常工作。

不同模塊的內存佈局可能不同。幾乎可以肯定地使用不同的分配器（這可以降低任何擁有內存的C++類型，包括string,vector和unique_ptr）。

使用指向純虛擬基類的指針可以幫助解決這個問題。或者，如果您有C++部分的源代碼，請嘗試將C++和C++/CLI鏈接到一個DLL中，而不是在單獨的DLL中引用C++代碼。