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std::bad_weak_ptr

Defined in header <memory>

Since C++11
class bad_weak_ptr;

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

exception <- bad_weak_ptr

Member functions

pub(constructor)constructs a new bad_weak_ptr object
(public member function)
puboperator=replaces the bad_weak_ptr object
(public member function)
pubwhatreturns the explanatory string
(public member function)

std::bad_weak_ptr::bad_weak_ptr

Since C++11
bad_weak_ptr() noexcept;                              (1)
bad_weak_ptr( const bad_weak_ptr& other ) noexcept; (2)

Constructs a new bad_weak_ptr object with an implementation-defined null-terminated byte string which is accessible through what().

  1. Default constructor.
  2. Copy constructor. If *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=

Since C++11
bad_weak_ptr& operator=( const bad_weak_ptr& other ) noexcept;

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

Since C++11
virtual const char* what() const noexcept;

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

pub(destructor) [virtual] destroys the exception object
(virtual public member function of std::exception)
pubwhat [virtual] returns an explanatory string
(virtual public member function of std::exception)

Example

#include <memory>
#include <iostream>
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 Result
std::bad_weak_ptr

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DRApplied toBehavior as publishedCorrect behavior
LWG 2376C++11calling what on a default-constructed bad_weak_ptr was required to return "bad_weak_ptr"the return value is implementation-defined

std::bad_weak_ptr

Defined in header <memory>

Since C++11
class bad_weak_ptr;

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

exception <- bad_weak_ptr

Member functions

pub(constructor)constructs a new bad_weak_ptr object
(public member function)
puboperator=replaces the bad_weak_ptr object
(public member function)
pubwhatreturns the explanatory string
(public member function)

std::bad_weak_ptr::bad_weak_ptr

Since C++11
bad_weak_ptr() noexcept;                              (1)
bad_weak_ptr( const bad_weak_ptr& other ) noexcept; (2)

Constructs a new bad_weak_ptr object with an implementation-defined null-terminated byte string which is accessible through what().

  1. Default constructor.
  2. Copy constructor. If *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=

Since C++11
bad_weak_ptr& operator=( const bad_weak_ptr& other ) noexcept;

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

Since C++11
virtual const char* what() const noexcept;

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

pub(destructor) [virtual] destroys the exception object
(virtual public member function of std::exception)
pubwhat [virtual] returns an explanatory string
(virtual public member function of std::exception)

Example

#include <memory>
#include <iostream>
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 Result
std::bad_weak_ptr

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DRApplied toBehavior as publishedCorrect behavior
LWG 2376C++11calling what on a default-constructed bad_weak_ptr was required to return "bad_weak_ptr"the return value is implementation-defined