[Boost-users] Re: Using MPL to write is_derived_from_std_basic_ostream

From: Jonathan Turkanis (technews_at_[hidden])
Date: 2004-09-02 12:42:21

"Angus Leeming" <angus.leeming_at_[hidden]> wrote in message
news:ch7h3d$466$1_at_sea.gmane.org...
> I'm trying to ascertain whether a given class is, or is derived from,
> std::basic_ostream, but I've ground to a halt.

I've attached a somewhat improved version inspired by your attempt. (Thanks!) It
only works on compilers which support has_xxx, but it should handle the case of
private inheritance now, by delegating to is_base_and_derived.

Note that with the current cvs it should not be necessary to write

    mpl::and_< mpl::bool_<has_char_type<U>::value>, ...

You can simply say

    mpl::and_< has_char_type<U>, ...

Best Regards,
Jonathan

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