std:: bad_weak_ptr
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Defined in header
<memory>
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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()
.
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.
|
The returned string is encoded with the ordinary literal encoding during constant evaluation. |
(since C++26) |
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
)
|
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[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) |