把以前VC6先寫(xiě)好的類加入VC7中，編譯時(shí)竟然錯(cuò)誤多到編譯器無(wú)法接受而停止，hooooo.真的好煩，要是有個(gè)工具修改外加的.h和cpp文件就好了...

遇到最多的是C2248編譯錯(cuò)誤，才發(fā)現(xiàn)VC7提升了對(duì)基類成員訪問(wèn)的檢測(cè)。

下面記錄一些MSDN里提到的

VC++編譯器重大修改

This topic summarizes the compile-time errors and warnings that will now be issued on code that compiled without errors or warnings in Visual Studio .NET or earlier versions.

• Closing parentheses now required for the defined preprocessor directive (C2004).
• Explicit specializations no longer find template parameters from primary template (C2146).
• A protected member (n) can only be accessed through a member function of a class (B) that inherits from the class (A) of which it (n) is a member (C2247).
• Improved accessibility checks in compiler now detect inaccessible base classes (C2248).
• An exception cannot be caught if the destructor and/or copy constructor is inaccessible (C2316).
• Default arguments on pointers to functions no longer allowed (C2383).
• A static data member cannot be initialized via derived class (C2477).
• The initialization of a typedef is not allowed by the standard and now generates a compiler error (C2513).
• bool is now a proper type (C2632).
• A UDC can now create ambiguity with overloaded operators (C2666).
• More expressions are now considered valid null pointer constants (C2668).
• template<> is now required in places where the compiler would previously imply it (C2768).
• The expilicit specialization of a member function ourside the class is not valid if the function has already been explicitly specialized via a template class specialization. (C2910).
• Floating point non-type template parameters are no longer allowed (C2993).
• Class templates are not allowed as template type arguments (C3206).
• Friend function names are no longer introduced into containing namespace (C3767).
• The compiler will no longer accept extra commas in a macro (C4002).
• An object of POD type constructed with an initializer of the form () will be default-initialized (C4345).
• typename is now required if a dependent name is to be treated as a type (C4346).
• Functions that were incorrectly considered template specializations are no longer considered so (C4347).
• Static data members cannot be initialized via derived class (C4356).
• A class template specialization needs to be defined before it was used in a return type (C4686).
• The compiler now reports unreachable code (C4702).

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?最煩人的在VC7里是無(wú)法訪問(wèn) private typedef！(C2248)但6.0卻是可以，累了。。。
Improved accessibility checks in compiler now detect inaccessible base classes (C2248).

C2248的產(chǎn)生原因之一：從“類”創(chuàng)建的對(duì)象無(wú)法訪問(wèn)該“類”的 protected 或 private 成員。

為使代碼在 Visual C++ 的 Visual Studio?.NET 2003 和 Visual Studio?.NET 版本中都有效，使用范圍運(yùn)算符。

// C2248c.cpp // compile with: /LD struct A { };struct B: private A { };struct C: B {void f(){A *p1 = (A*) this; // C2248::A *p2 = (::A*) this; // OK} };

如果調(diào)試器表達(dá)式引用不明確的成員名稱，必須使用類名稱來(lái)限定它。
例如，如果 CObject 是 CClass 實(shí)例，后者從 AClass 和 BClass
二者中繼承了名為 expense 的成員函數(shù)，則 CObject.expense 是不明確的。
可以按如下方式化解多義性：

CObject.BClass::expense

轉(zhuǎn)載于:https://www.cnblogs.com/babyblue/archive/2005/05/28/164210.html

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