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Editorial Team
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Asked: 2026-05-19T10:22:59+00:00

Which is more correct? And Why. On work I recently run in a discussion

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Which is more correct? And Why.

On work I recently run in a discussion how to do a specific template specialization.

This way:

template <typename T, bool someBoolVar = is_polymorphic<T>::value>
struct SomeTemplate { // with empty definition
};

template <typename T>
struct SomeTemplate<T, true> {
  ...
};

template <typename T>
struct SomeTemplate<T, false> {
  ...
};

or this way:

template <typename T, bool someBoolVar = is_polymorphic<T>::value>
struct SomeTemplate; // without empty definition           -- difference here

template <typename T>
struct SomeTemplate<T, true> {
  ...
};

template <typename T>
struct SomeTemplate<T, false> {
  ...
};
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1 Answer

  1. Editorial Team

    Neither. Because both will not compile! Wrong syntax for partial specialization!

    This is how partial specialization is done:

    //correct syntax
template <typename T>
struct SomeTemplate<T,false> {
  ...
};

    Not this:

    //wrong syntax
template <typename T, false>
struct SomeTemplate {
  ...
};

    Now answer to your question assuming you’ll fix the syntax!

    In my opinion, the second approach is rational, because bool can have ONLY two values, so three versions of SomeTemplate class template doesn’t make sense at all, which you’re doing in the first approach.

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