Template variable as unordered_map key, issue with iterator

Question

I try to use boost unordered_map with key as template variable.

 template<typename T>
std::string CPerformanceWatcher<T>::CheckPerformance(T &sOrderID, bool bDeleteRecord)
{
        boost::unordered_map<T, int>::iterator iter;
        iter = m_OrderIDTimeValMap->find(sOrderID);
        if(iter == m_OrderIDTimeValMap->end())
        {
            return false;
        }
        return false;
}

But the compile complains with syntax error. So my question is if I cannot use such an iterator?

possible duplicate of [Where and why do I have to put the "template" and "typename" keywords?](http://stackoverflow.com/questions/610245/where-and-why-do-i-have-to-put-the-template-and-typename-keywords) — jrok, Oct 04 '13 at 07:23

score 3 · Accepted Answer · edited May 23 '17 at 12:21

3

You need to resolve the dependent name using typename keyword:

typename boost::unordered_map<T, int>::iterator iter;

See for more info on dependent names:

http://en.cppreference.com/w/cpp/language/dependent_name

How do you understand dependent names in C++

edited May 23 '17 at 12:21

Community

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answered Oct 04 '13 at 07:17

goji

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Template variable as unordered_map key, issue with iterator

1 Answers1