How i could compare the data type of each tuple argument?
enum WinGetCmds {
WINGET_TITLE, WINGET_CLASS
};
template <typename... Args>
auto WinGet(WinGetCmds cmd, Args&&... args)
{
auto pack = std::make_tuple(std::forward<Args>(args)...);
switch (cmd)
{
case WINGET_TITLE:
{
auto arg_1 = std::get<0>(pack);
if constexpr (std::is_same<arg_1, std::wstring>::value)
{
//...
}
else if constexpr (std::is_same<arg_1, HWND>::value)
{
//...
}
}
break;
}
}
WinGet(WINGET_TITLE, L"ABC");
In the template above I’m getting an error in the constexpr line:
'std::is_same': 'arg_1' is not a valid template type argument for parameter '_Ty1'7
What other way I could compare the data type of arg_1?
>Solution :
What other way I could compare the data type of arg_1?
The problem is that arg_1 is an expression when you use it in an expression. That is, you cannot use it as a template type parameter for is_same which is what the error is trying to say.
To solve this, you could use, decltype(arg_1).