Article ID: 249045
Article Last Modified on 7/5/2005
APPLIES TO
- Microsoft Visual C++ 6.0 Enterprise Edition
- Microsoft Visual C++ 6.0 Professional Edition
- Microsoft Visual C++ 6.0 Standard Edition
This article was previously published under Q249045
SYMPTOMS
The compiler generates an error such as the following when a pointer-to-member is used as a class template parameter.
CAUSE
This C++ language feature has not yet been implemented in Visual C++.
RESOLUTION
To not use the pointer-to-member as a template argument, pass it as a parameter to the class constructor.
STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.
MORE INFORMATION
Use the following sample code to reproduce the behavior:
#ifdef BUG
struct MyClass {
char a,b;
MyClass() : a('a'), b('b') {};
};
template<char MyClass::*member_ptr>
class AnotherClass {
private:
MyClass m_var;
public:
char value() { return m_var.*member_ptr; }
};
int main()
{
AnotherClass<&MyClass::a> var1;
AnotherClass<&MyClass::b> var2; //<<<< Causes compiler error.
return 0;
}
#else
// WORKAROUND
struct MyClass {
char a,b;
MyClass() : a('a'), b('b') {};
};
template<typename MbrType, typename ClassType>
class AnotherClass {
private:
MyClass m_var;
MbrType ClassType::*member_ptr;
public:
AnotherClass(MbrType ClassType::*mem_ptr) : member_ptr(mem_ptr) {}
char value() { return m_var.*member_ptr; }
};
int main()
{
AnotherClass<char,MyClass> var1(&MyClass::a);
AnotherClass<char,MyClass> var2(&MyClass::b);
return 0;
}
#endif
Keywords: kbbug kblangcpp kbtemplate kbcpponly kbpending kbcompiler KB249045
