std::exception::exception(3)

NAME
std::exception::exception - std::exception::exception

Synopsis
   exception() throw(); (until C++11)
   exception() noexcept; (1) (since C++11)
   exception( const exception& other ) throw(); (2) (until C++11)
   exception( const exception& other ) noexcept; (since C++11)
   Constructs new exception object.
   1) Default constructor. what() returns an implementation-defined string.
   2) Copy constructor. Initializes the contents with those of other. If *this and
   other both have dynamic type std::exception then std::strcmp(what(), other.what())
   == 0.

Parameters
   other - another exception to assign the contents of

Notes
   Because copying std::exception is not permitted to throw exceptions, when derived
   classes (such as std::runtime_error) have to manage a user-defined diagnostic
   message, it is typically implemented as a copy-on-write string.
   The Microsoft implementation includes non-standard constructors taking strings thus
   allowing instances to be thrown directly with a meaningful error message. The
   nearest standard equivalents are std::runtime_error or std::logic_error.
   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 471 C++98 there is no requirement on what() of the added
                      exception copy