std::exception::exception
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(1)
exception() throw();
(until C++11)
exception() noexcept;
(since C++11) (constexpr since C++26)
(2)
exception( const exception& other ) throw();
(until C++11)
exception( const exception& other ) noexcept;
(since C++11) (constexpr since C++26)
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.[edit] Parameters
other
-
another exception to assign the contents of
[edit] 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 .
[edit] 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 exception copy | added |