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/C++std::bad_weak_ptr
Defined in header <memory> | ||
|---|---|---|
class bad_weak_ptr; | (since C++11) |
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.
Member functions
| (constructor) | constructs a new bad_weak_ptr object (public member function) |
| operator= | replaces the bad_weak_ptr object (public member function) |
| what | returns the explanatory string (public member function) |
std::bad_weak_ptr::bad_weak_ptr
bad_weak_ptr() noexcept; | (1) | (since C++11) |
bad_weak_ptr( const bad_weak_ptr& other ) noexcept; | (2) | (since C++11) |
Constructs a new bad_weak_ptr object with an implementation-defined null-terminated byte string which is accessible through what().
*this and other both have dynamic type std::bad_weak_ptr then std::strcmp(what(), other.what()) == 0.Parameters
| other | - | another exception object to copy |
std::bad_weak_ptr::operator=
bad_weak_ptr& operator=( const bad_weak_ptr& other ) noexcept; | (since C++11) |
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
| other | - | another exception object to assign with |
Return value
*this.
std::bad_weak_ptr::what
virtual const char* what() const noexcept; | (since C++11) |
Returns the explanatory string.
Parameters
(none).
Return value
Pointer to a 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
|
[virtual] | destroys the exception object (virtual public member function of std::exception) |
|
[virtual] | returns an explanatory string (virtual public member function of std::exception) |
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
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 |
See also
|
(C++11) | smart pointer with shared object ownership semantics (class template) |
|
(C++11) | weak reference to an object managed by std::shared_ptr (class template) |
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