Re: [Boost-users] boost static assert and is_base_of question.

From: John Maddock (john_at_[hidden])
Date: 2007-08-10 04:45:32

chun ping wang wrote:
>> Hi, how would I ensured that class U of template class is a dervied
>> class of boost::operators<U> using BOOST_STATIC_ASSERT and
>> boost::is_base_of...
>>
>> template <T>
>> myFunc(const T& a)
>> {
>>    typedef boost::operators<T> operatorT;
>>    BOOST_STATIC_ASSERT(is_integral<T>::value || is_base_of<operatorT,
>>>>> value);
>>    // ... other codes.
>> }
>>
>> doing this gives me an error.

Right, since BOOST_STATIC_ASSERT is a macro, you need some extra parenthesis 
to stop the "," in the template arg list to is_base_of from being seen as a 
macro-argument separator:

BOOST_STATIC_ASSERT((is_base_of<A, B>::value));

HTH, John.