http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57283
--- Comment #2 from Lin Yi-Li <record.nctu.cis91 at gmail dot com> --- Sorry I missed that 'pm is a pointer to member function...'. I know that C++11 has lambda, but using std::mem_fn is sometimes much clear. But according to standard, value from std::mem_fn for variable will not be able to work with std::not1. Even if the usage is similiar to the one for member function takes no argument. So is it possible to be an enhancement?