I am watching the following video
It is mentioned here that g++ will report an error for the following code:
#include<vector>
#include<typeinfo>
#include<iostream>
struct S
{
std::vector<std::string> b ;
};
int main()
{
S s;
std::cout << typeid(S::b).name();
}
error: invalid use of non-static data member ‘S::b’
But I did not encounter this kind of error under msvc and clang. Who is right and why? And why is it changed to
typeid(&S::b).name();
Is the result correct afterwards?
Gcc is wrong (Bug 68604). S::b
is an id-expression referring to a non-static data member, which could be used only in unevaluated context. Gcc seems failing in taking this as unevaluated expression.
As the workaround you could:
std::cout << typeid(decltype(S::b)).name();
Note that in typeid(&S::b).name();
, &S::b
gives a pointer to member; the result is different with using S::b
.