AlisdairM wrote:
I am a little confused by the result_of tests, which means either I don't understand the library, or there is a problem as most compilers are passing!
The basic case:
struct int_result_type { typedef int result_type; };
BOOST_STATIC_ASSERT (( is_same< result_of< int_result_type(float) >::type, int >::value ));
If I understand correctly, this is asking what is the result_of a function taking a float and returning an int_result_type.
No, this is a common misunderstanding of result_of. result_of<F(X)> asks "what is the return type of f(x), where f is of type F and x is of type X?" So in the above case, it asks what the result would be if we were to create an instance of int_result_type and call it with 1.0f. The correct answer is, of course, "a compile time error", but the TR1 spec forces result_of to report 'int' for the usual reasons. :-)