c++ - Specializing a base class' member function in a derived class template -

have @ code:

struct foo {     virtual int bleh() {         return 42;     } };   template<typename t> struct bar : public foo {  };  // error template<> int bar<char>::bleh() {     return 12; } 

i'm trying provide definition of base::bleh bar<char>, compiler(gcc 4.7.2) rejects code following diagnostic:

template-id ‘bleh<>’ ‘int bar<char>::bleh()’ not match template declaration 

it seems base::bleh somehow hidden in bar. i've fixed using following definition in bar:

template<typename t> struct bar : public foo {     // doesn't work     //using foo::bleh;       // works     int bleh() {         return foo::bleh();     } }; 

but i'm curious of why fails compile. why compiler rejecting code?

in non-compiling example, you're attempting specialize , define function hasn't been declared in template definition of bar ... in later example have declared defined non-specialized version of function inside template definition of bar, why compiles. can tell, here associated language in standard concerning why first version won't compile (14.7.3/4):

a member function, member function template, member class, member enumeration, member class template, or static data member of class template may explicitly specialized class specialization implicitly instantiated; in case, definition of class template shall precede explicit specialization member of class template