Re: [Boost-users] Determine at compile time whether type has subtraction semantics?

18 Feb 2011

      AMDG

On 2/18/2011 9:50 AM, John Reid wrote:
...
Is it possible to determine at compile-time if a type has subtraction
semantics? E.g. in struct A<T> I would like to decide at compile-time
not to execute &A::subtract in the register_fns method. Then the
subtract method is not instantiated and there is no error.
template< typename T >
struct A {
void register_fns() {
&A::subtract;
}
T subtract( T x, T y ) {
return x - y;
}
};
void test() {
A< int >().register_fns(); // int: Fine
A< std::string >().register_fns(); // string: Compile error
}
I didn't see anything in Boost.TypeTraits
I believe the type traits extensions in the
review queue handle this.

In Christ,
Steven Watanabe