CODEWITHSUNDEEP
c++templatesc++03
Jack
Jack

Reputation: 65

Force unsigned type into C++ template typename

I'm very new in C++ and template. I have a template class in C++03 and I want to force the given type always be unsigned. For example:

template <typename T>
class Test
{
    T _var1;
};

I want to force T to be always unsigned such as uint8_t, uint16_t, unsigned int, ... and fail if the given type is signed. Is this possible to do in C++? If so can someone shows how?

Thank you

Upvotes: 1

Views: 571

Answers (1)

aschepler
aschepler

Reputation: 72271

This is tricky in C++03 (but easy in C++11). Boost provides a legible and portable way:

#include <limits>
#include <boost/static_assert.hpp>

template <typename T>
class Test
{
    BOOST_STATIC_ASSERT_MSG(std::numeric_limits<T>::is_integer &&
                            !std::numeric_limits<T>::is_signed,
                            "T must be an unsigned integer type");
    // ...
};

Upvotes: 2

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