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 <class T, void (T::*)() const > struct test_for_member_go{ }; template<class T> static Found test_for_go(test_for_member_go<T,&T::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. -- Joel FALCOU Research Engineer @ Institut d'Electronique Fondamentale Université PARIS SUD XI France