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c++builder 泛型
http://docwiki.embarcadero.com/RADStudio/XE6/en/How_to_Handle_Delphi_Generics_in_C%2B%2B
这个泛型是为delphi编写的，c++builder不能直接使用，非要用的话按下面的例子，先建立个delphiunit，集成新类，然后再c++builder引用此单元头文件，就可以了。真麻烦。
How to Handle Delphi Generics in C++
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This topic describes some programming issues that you might encounter when dealing with generics, a feature supported by Delphi.
Delphi generics are exposed to C++ as templates. However, it is important to realize that the instantiations occur on the Delphi side, not in C++. Therefore, you can only use these template for types that were explicitly instantiated in Delphi code. For example, let‘s declare a simple generic, TList<T>, in Delphi:
unit DelphiUnit; interface uses System.Generics.Collections; type MyTList<T> = class(TList<T>) public // Anchors constructor/destructor constructor Create; destructor Destroy; override; class procedure Cleanup(var L: MyTList<T>); static; end; // DoubleList: instantiates MyTList<double> DoubleList = class(MyTList<double>) end; // StringList: instantiates MyTList<string> StringList = class(MyTList<string>) end; implementation class procedure MyTList<T>.Cleanup(var L: MyTList<T>);begin L.Free;end; constructor MyTList<T>.Create;begin inherited;end; destructor MyTList<T>.Destroy;begin inherited;end; end.The interface above is exposed to C++ as the following:
// CodeGear C++Builder// Copyright (c) 1995, 2012 by Embarcadero Technologies, Inc.// All rights reserved // (DO NOT EDIT: machine generated header) ‘DelphiUnit.pas‘ rev: 24.00 (Windows) #ifndef DelphiunitHPP#define DelphiunitHPP #pragma delphiheader begin#pragma option push#pragma option -w // Display all warnings#pragma option -w-inl // Functions %s are not expanded inline#pragma option -w-8111 // Accessing deprecated entity#pragma option -Vx // Zero-length empty class member#pragma pack(push,8)#include <System.hpp> // Pascal unit#include <SysInit.hpp> // Pascal unit#include <System.Generics.Collections.hpp> // Pascal unit#include <System.Generics.Defaults.hpp> // Pascal unit#include <System.Types.hpp> // Pascal unit //-- user supplied ----------------------------------------------------------- namespace Delphiunit{//-- type declarations -------------------------------------------------------template<typename T> class DELPHICLASS MyTList__1;// Template declaration generated by Delphi parameterized types is// used only for accessing Delphi variables and fields.// Don‘t instantiate with new type parameters in user code.template<typename T> class PASCALIMPLEMENTATION MyTList__1 : public System::Generics::Collections::TList__1<T>{ typedef System::Generics::Collections::TList__1<T> inherited; public: __fastcall MyTList__1(void); __fastcall virtual ~MyTList__1(void); static void __fastcall Cleanup(MyTList__1<T>* &L);}; class DELPHICLASS DoubleList;class PASCALIMPLEMENTATION DoubleList : public MyTList__1<double>{ typedef MyTList__1<double> inherited; public: /* {DelphiUnit}MyTList<System_Double>.Create */ inline __fastcall DoubleList(void) : MyTList__1<double>() { } /* {DelphiUnit}MyTList<System_Double>.Destroy */ inline __fastcall virtual ~DoubleList(void) { } }; class DELPHICLASS StringList;class PASCALIMPLEMENTATION StringList : public MyTList__1<System::UnicodeString>{ typedef MyTList__1<System::UnicodeString> inherited; public: /* {DelphiUnit}MyTList<System_string>.Create */ inline __fastcall StringList(void) : MyTList__1<System::UnicodeString>() { } /* {DelphiUnit}MyTList<System_string>.Destroy */ inline __fastcall virtual ~StringList(void) { } }; //-- var, const, procedure ---------------------------------------------------} /* namespace Delphiunit */#if !defined(DELPHIHEADER_NO_IMPLICIT_NAMESPACE_USE) && !defined(NO_USING_NAMESPACE_DELPHIUNIT)using namespace Delphiunit;#endif#pragma pack(pop)#pragma option pop #pragma delphiheader end.//-- end unit ----------------------------------------------------------------#endif // DelphiunitHPPC++ code linking with the .obj created from the above Delphi unit can use instances of MyTList__1<double> or MyTList__1<System::String>.
void UseDLists(){ // C++ code can use the Generics defined in Delphi directly // as long as the C++ code limits itself to types for which // the generic was instantiated on the Delphi side. For example, // since the Delphi Unit instantiates MyTList<String> // and MyTList<double> we can use these here. // However, if we try to use MyTList__1<char> we‘ll get // errors since the Delphi side did not instantiate // MyTList<AnsiChar>. MyTList__1<double>* dblList = new MyTList__1<double>(); dblList->Add(1.0); dblList->Add(1.5); double d = dblList->Items[1];#ifdef _WIN64 delete dblList#else MyTList__1<double>::Cleanup(dblList);#endif MyTList__1<System::String> *strList = new MyTList__1<System::String>(); strList->Add("First"); strList->Add("Second"); strList->Add("Third"); assert(strList->Count == 3); System::String str = strList->Items[0]; assert(str == "First"); assert(strList->Items[1] == "Second"); assert(strList->Items[2] == "Third"); strList->Insert(0, "Inserted"); assert(strList->Count == 4); assert(strList->Items[0] == "Inserted"); assert(strList->Items[1] == "First"); strList->Reverse(); assert(strList->Items[0] == "Third"); assert(strList->Items[1] == "Second"); assert(strList->Items[2] == "First"); assert(strList->Items[3] == "Inserted"); assert(strList->Contains("Inserted")); assert(!strList->Contains("Not Inserted")); strList->Sort(); strList->Remove("Inserted"); assert(strList->Items[0] == "First"); assert(strList->Items[1] == "Second"); assert(strList->Items[2] == "Third"); #ifdef _WIN64 delete strList;#else MyTList__1<System::String>::Cleanup(strList);#endif}If C++ code attempts to use a Delphi generic for types that were not instantiated in Delphi, you‘ll get errors at link time. For example, the following code attempts to use MyTList__1<char> when the Delphi code did not explicitly instantiate MyTList<AnsiChar>:
void UseListOfChar(){ MyTList__1<char>* charList = new MyTList__1<char>(); charList->Add(‘a‘); // ...}While the code above compiles, the following errors are generated at link time:
[ilink32 Error] Error: Unresolved external ‘Delphiunit::MyTList__1<char>::‘ referenced from CPPUNIT.OBJ[ilink32 Error] Error: Unresolved external ‘__fastcall Delphiunit::MyTList__1<char>::MyTList__1<char>()‘ referenced from CPPUNIT.OBJ[ilink32 Error] Error: Unresolved external ‘__fastcall System::Generics::Collections::TList__1<char>::Add(const const char)‘ referenced from CPPUNIT.OBJ[ilink32 Error] Error: Unable to perform linkTo eliminate the error, you have to make sure that the Delphi code uses the type MyTList<AnsiChar>.
c++builder 泛型
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