virtual const char* what() const throw();
virtual const char* what() const noexcept;
Returns the explanatory string.
 Return value
Pointer to a null-terminated string with explanatory information. The pointer is guaranteed to be valid at least until the exception object from which it is obtained is destroyed, or until a non-const member function on the exception object is called.
 Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
|DR||Applied to||Behavior as published||Correct behavior|
|LWG 108||C++98||it was unspecified when the returned pointer becomes invalid||specified|