c++ - constexpr and bizzare error -

i'm having:

constexpr bool is_concurrency_selected()const     {         return concurrentgbx->ischecked();//gbx groupbox checkbox     } 

and i'm getting error:

c:\...\options_dialog.hpp:129: error: enclosing class of 'bool options_dialog::is_concurrency_selected() const' not literal type 

any thoughts on why?

it means class not literal type... program invalid, because options not literal class type. checker literal type.

struct checker {   constexpr bool ischecked() {     return false;   } };  struct options {   options(checker *concurrentgbx)     :concurrentgbx(concurrentgbx)   { }    constexpr bool is_concurrency_selected()const   {       //gbx groupbox checkbox       return concurrentgbx->ischecked();   }    checker *concurrentgbx; };  int main() {   static checker c;   constexpr options o(&c);   constexpr bool x = o.is_concurrency_selected(); } 

clang prints

test.cpp:12:18: error: non-literal type 'options' cannot have constexpr members     constexpr bool is_concurrency_selected()const                    ^ test.cpp:7:8: note: 'options' not literal because not aggregate , has no constexpr constructors other copy or move constructors     struct options { 

if fix , make options constructor constexpr, example snippet compiles. similar things may apply code.

you appear not understand constexpr means. recommend reading book (if such book exists already, anyway).