Search code examples
c++unordered-mapemplace

unordered_map emplace compile error

I have the following code in myclass.h file:

typedef std::unordered_set< int, int> Parameters;
class MyClass
{
    public:
        void myFunction();
    private:
        Parameters* m_params;
}

Then, myFunction looks as follows:

void MyClass::myFunction()
{
    ...
    m_params->emplace(1,1);
}

When I try to compile, I get:

term does not evaluate to a function taking 1 arguments

If I comment the emplace line, the error disappears. However, I don't find any misuse related to this function signature: http://en.cppreference.com/w/cpp/container/unordered_map/emplace

Any help would be much appreciated.

Solution

  • Simple typo: You used std::unordered_set in your code, but you meant std::unordered_map.

    Your implementation doesn't recognise any error setting Hash to int in the std::unordered_set template until you try to put something into the container. Then it tries to hash the input, and realises it can't use an int as a function.