std::bad_weak_ptr
<memory>
std::bad_weak_ptr is the type of the object thrown as exceptions by the constructors of std::shared_ptr that take std::weak_ptr as the argument, when the std::weak_ptr refers to an already deleted object.
Inheritance diagram
Contents
[edit] Member functions
bad_weak_ptr object (public member function)
bad_weak_ptr object (public member function)
(public member function)
std::bad_weak_ptr::bad_weak_ptr
Constructs a new bad_weak_ptr object with an implementation-defined null-terminated byte string which is accessible through what().
std::bad_weak_ptr then std::strcmp (what(), other.what()) == 0.Parameters
std::bad_weak_ptr::operator=
Assigns the contents with those of other. If *this and other both have dynamic type std::bad_weak_ptr then std::strcmp (what(), other.what()) == 0 after assignment.
Parameters
Return value
*this
std::bad_weak_ptr::what
Returns the explanatory string.
Return value
Pointer to an implementation-defined null-terminated string with explanatory information. The string is suitable for conversion and display as a std::wstring . 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 (e.g. copy assignment operator) on the exception object is called.
Notes
Implementations are allowed but not required to override what().
Inherited from std::exception
Member functions
[edit] Example
#include <iostream> #include <memory> int main() { std::shared_ptr <int> p1(new int(42)); std::weak_ptr <int> wp(p1); p1.reset(); try { std::shared_ptr <int> p2(wp); } catch (const std::bad_weak_ptr& e) { std::cout << e.what() << '\n'; } }
Possible output:
std::bad_weak_ptr
[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 2376 | C++11 | calling what on a default-constructed bad_weak_ptr was required to return "bad_weak_ptr"
|
the return value is implementation-defined |