23 General utilities library [utilities]

23.14 Function objects [function.objects]

23.14.13 Polymorphic function wrappers [func.wrap]

23.14.13.1 Class bad_function_call [func.wrap.badcall]

An exception of type bad_function_call is thrown by function::operator() ([func.wrap.func.inv]) when the function wrapper object has no target.

namespace std {
  class bad_function_call : public exception {
  public:
    // [func.wrap.badcall.const], constructor
    bad_function_call() noexcept;
  };
}

23.14.13.1.1 bad_function_call constructor [func.wrap.badcall.const]

bad_function_call() noexcept;

Effects: Constructs a bad_function_call object.

Postconditions: what() returns an implementation-defined ntbs.