C++ template gotchas

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just now I had to dig through the website to find out why template class template member function was giving syntax errors:

template<class C> class F00 {
   template<typename T> bar();
};
...
Foo<C> f;
f.bar<T>(); // syntax error here

I now realize that template brackets are treated as relational operators. To do what was intended the following bizarre syntax is needed, cf Templates: template function not playing well with class's template member function:

f.template bar<T>();

what other bizarre aspects and gotcha of C++/C++ templates you have encountered that were not something that you would consider to be common knowledge?

templates c++
4 Answers

Out of scope class member function definition:

template <typename T> 
class List {                     // a namespace scope class template 
  public: 
    template <typename T2>       // a member function template 
    List (List<T2> const&);      // (constructor) 
    … 
}; 
template <typename T> 
 template <typename T2> 
List<T>::List (List<T2> const& b) // an out-of-class member function 
{                                 // template definition 
    … 
}
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