C++ GCC 错误：非命名空间范围内的显式特化
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GCC error: explicit specialization in non-namespace scope
提问by Ryan
I am trying to port the following code. I know the standard doesn't allow explicit specialization in non-namescape scope and I should use overloading, but I just can't find a way to apply this technique in this particular case.
我正在尝试移植以下代码。我知道标准不允许在非 namescape 范围内进行显式专业化，我应该使用重载，但我只是找不到在这种特殊情况下应用这种技术的方法。
class VarData
{
public:
template < typename T > bool IsTypeOf (int index) const
{
return IsTypeOf_f<T>::IsTypeOf(this, index); // no error...
}
template <> bool IsTypeOf < int > (int index) const // error: explicit specialization in non-namespace scope 'class StateData'
{
return false;
}
template <> bool IsTypeOf < double > (int index) const // error: explicit specialization in non-namespace scope 'class StateData'
{
return false;
}
};
回答by CB Bailey
You just have to move your specializations of the member templates outside of the class body.
您只需要将成员模板的特化移到类主体之外。
class VarData
{
public:
template < typename T > bool IsTypeOf (int index) const
{
return IsTypeOf_f<T>::IsTypeOf(this, index);
}
};
template <> bool VarData::IsTypeOf < int > (int index) const
{
return false;
}
template <> bool VarData::IsTypeOf < double > (int index) const
{
return false;
}
回答by Nawaz
Define the specialization outside the class as:
将类外的专业化定义为：
template <>
bool VarData::IsTypeOf < int > (int index) const
{ //^^^^^^^^^ don't forget this!
return false;
}
template <>
bool VarData::IsTypeOf < double > (int index) const
{ //^^^^^^^ don't forget this!
return false;
}
