最近在用C++Builder时,想要将对象1的成员函数指针赋给对象2的成员变量,然后在对象2内通过该成员变量访问对象1的成员函数。貌似标准的C++不支持这样的操作,但是C++Builder提供了__closure关键字,感觉还挺好用的,测试代码如下:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | // Unit1.h //--------------------------------------------------------------------------- class Test1 { private : int m_Add; public : __fastcall Test1( int Add) { m_Add = Add; }; virtual __fastcall ~Test1() {}; int __fastcall TestFunction1( int param1); void __fastcall Test11(); }; //--------------------------------------------------------------------------- class Test2 { public : __fastcall Test2() {}; virtual __fastcall ~Test2() {}; int __fastcall(__closure *TestFunction2)( int param1); void __fastcall Test22(); }; |
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 | // Unit1.cpp //--------------------------------------------------------------------------- int __fastcall Test1::TestFunction1( int param1) { return param1 + m_Add; } //--------------------------------------------------------------------------- void __fastcall Test1::Test11() { Test2 *test2 = new Test2(); test2->TestFunction2 = &TestFunction1; test2->Test22(); delete test2; }; //--------------------------------------------------------------------------- void __fastcall Test2::Test22() { printf ( "Result: %d" , TestFunction2(1)); } |
01 02 03 04 05 06 07 08 09 | // main.cpp //--------------------------------------------------------------------------- int _tmain( int argc, _TCHAR* argv[]) { Test1 *test = new Test1(1); test->Test11(); delete test; getchar (); return 0; } |
A few years ago I’d have to pay soomene for this information.