c++ - "non-standard syntax; use '&' to create a pointer to member" error in Visual Studio 2015

Question

I have this function:

std::string Room::getUsersAsString(std::vector<User*> usersList, User * excludeUser)
{
    std::string usersNames = " ";

    for (int i = 0; i < usersList.size(); i++) {
        if (usersList[i]->getUsername() != excludeUser->getUsername) {
            usersNames.append(usersList[i]->getUsername);
            usersNames.append(" ");
        }
    }

    return usersNames;
}

Whenever I try to run the program, I get the following error:

non-standard syntax; use '&' to create a pointer to member

How can I fix it?

Answer 1

If you use

if (usersList[i]->getUsername() != excludeUser->getUsername)

instead of

if (usersList[i]->getUsername() != excludeUser->getUsername())

your compiler will think you want to use a function pointer instead of the method itself, and if you would have wanted to use a function pointer, you would still have to get the address of it (using &).

So make sure you don't forget your () after a function call!