Namespace-scope anonymous unions must be declared static unless they appear in an unnamed namespace. Union-like classes Aunion-like classis either a union, or a (non-union) class that has at least one anonymous union as a member. A union-like class has a set ofvariant members: ...
Declares a class type which will be defined later in this scope. Until the definition appears, this class name hasincomplete type. This allows classes that refer to each other: classVector;// forward declarationclassMatrix{// ...friendVector operator*(constMatrix&,constVector&);};classVector{...
enumE{x};voidf(){intE;usingenumE;// OK}usingF=E;usingenumF;// OKtemplate<classT>usingEE=T;voidg(){usingenumEE<E>;// OK} Ausingenumdeclaration introduces the enumerator names of the named enumeration as if by ausingdeclarationfor each enumerator. When in class scope, ausingenumdeclarat...
nested-name-specifier - a sequence of names and scope resolution operators :: attr - (since C++11) a list of attributes cv - const/volatile qualification which apply to the pointer that is being declared (not to the pointed-to type, whose qualifications are part of declaration specifier ...
std::string& f() { std::string s = "Example"; return s; // exits the scope of s: // its destructor is called and its storage deallocated } std::string& r = f(); // dangling reference std::cout << r; // undefined behavior: reads from a dangling reference std::string s =...
When a local class declares an unqualified function or class as a friend, only functions and classes in the innermost non-class scope arelooked up, not the global functions: classF{};intf();intmain(){externintg();classLocal// Local class in the main() function{friendintf();// Error,...
typename-the keywordtypenamemay be used as necessary to resolvedependent names, when the using-declaration introduces a member type from a base class into a class template nested-name-specifier-a sequence of names and scope resolution operators::, ending with a scope resolution operator. A single...
A function declaration at class scope introduces a class member function (unless the friend specifier is used), see member functions and friend functions for details. noptr-declarator ( parameter-list ) cv (optional) ref (optional) except (optional) attr (optional...