c++ - "Declaration does not declare anything" and "expected unqualified-id" -

compiling code in visual studio totally fine.

bool check(void);  bool check(void) { return true; } 

but in xcode(apple llvm) warning on declaration

declaration not declare 

and error on definition

parse error: expected unqualified-id 

what going on here? how can fix this?

iirc on mac there exists macro "check" interfere function name. try mycheck.