That is a beautiful trick. The sizeof trick basically. "C++ template metaprogramming" p212 As Joel says in that post, it should definitely be included in standard boost. Perhaps in the type traits library? thank you,

----- Original Message ----- From: "Igor R" To: boost-users@lists.boost.org Subject: Re: [Boost-users] behavior conditional on template argument Date: Wed, 21 Jan 2009 13:17:56 +0200

...

You can use enable_if to let the compiler decide which one it should instantiate. And the argument will be a custom defined type trait. I think there are facilities to automatically define it on the presence of a type, there may be soemthing for fucntions as well, but I don't remember where they live (MPL ?)

Here it is: http://www.nabble.com/compile-time-check-that-a-member-function-exists-td185...

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