Re: [Boost-users] compile-time check that a member function exists

Thank you very much. That worked great. John Joel FALCOU wrote:

John Pretz a écrit :

...

Hi,

I'm pretty new to boost. I want to write some code with a compile-time check whether a member function exists or not. The code below shows kinda what I need except I'd obviously like to avoid a specialized template for each class that I use.

Can anybody point me in the right direction?

Not sure if it exists in boost, but the good old trick using the (...) operator may be enough. Like :

typedef char NotFound; struct Found { char x[2]; };

template struct test_for_member_go{ }; template<class T> static Found test_for_go(test_for_member_go*); template<class T> static NotFound test_for_go( ... );

template<class T> struct test { static const bool value = (sizeof( test_for_go<T>( 0 ) ) == sizeof(Found)); typedef boost::mpl::bool_<value> type; };

then test<X>::type should give you a CT boolean that indicates if go is a member of T. This could be easily turned into a macro-like features that can be retargeted for any member with any signature.

-- John Pretz -- P-23, MS H803 Los Alamos National Lab Los Alamos, NM 87545 Phone: (505)665-5847 Fax: (505)665-4121