标签:c++类 ble stat func exp int() hat mes let
特化需要在命名空间里做,不能在类中直接特化一个类模板,但可以放到类外来做。也可在类之内用偏特化,然后传入一个dummy template argument。
来源:https://stackoverflow.com/questions/3052579/explicit-specialization-in-non-namespace-scope
template<typename T>
class CConstraint
{
public:
CConstraint()
{
}
virtual ~CConstraint()
{
}
template <typename TL>
void Verify(int position, int constraints[])
{
}
template <>
void Verify<int>(int, int[])
{
}
};
Compiling this under g++ gives the following error:
Explicit specialization in non-namespace scope ‘class CConstraint‘
In VC, it compiles fine. Can anyone please let me know the workaround?
原因:
VC++ is non-compliant in this case - explicit specializations have to be at namespace scope. C++03, §14.7.3/2:
An explicit specialization shall be declared in the namespace of which the template is a member, or, for member templates, in the namespace of which the enclosing class or enclosing class template is a member.
An explicit specialization of a member function, member class or static data member of a class template shall be declared in the namespace of which the class template is a member.
Additionally you have the problem that you can‘t specialize member functions without explicitly specializing the containing class due to C++03, §14.7.3/3, so one solution would be to let Verify() forward to a, possibly specialized, free function:namespace detail {
template <typename TL> void Verify (int, int[]) {}
template <> void Verify<int>(int, int[]) {}
}
template<typename T> class CConstraint {
// ...
template <typename TL> void Verify(int position, int constraints[]) {
detail::Verify<TL>(position, constraints);
}
};
来源:https://www.zhihu.com/question/54468727
class A {
public:
template <typename T, typename = void>
struct B { T value; };
template <typename X>
struct B<int, X> { bool value; };
B<double> dvalue;
B<int> ivalue;
};
标签:c++类 ble stat func exp int() hat mes let
原文地址:https://www.cnblogs.com/gelare/p/12714915.html