std::bad_cast
Defined in header <typeinfo> |
||
---|---|---|
class bad_cast : public std::exception; |
An exception of this type is thrown when a dynamic_cast
to a reference type fails the run-time check (e.g. because the types are not related by inheritance), and also from std::use_facet
if the requested facet does not exist in the locale.
Inheritance diagram.
Member functions
(constructor)
|
constructs a new bad_cast object (public member function) |
operator=
|
replaces the bad_cast object (public member function) |
what
|
returns the explanatory string (public member function) |
std::bad_cast::bad_cast
(1) | ||
bad_cast() throw(); |
(until C++11) | |
bad_cast() noexcept; |
(since C++11) | |
(2) | ||
bad_cast( const bad_cast& other ) throw(); |
(until C++11) | |
bad_cast( const bad_cast& other ) noexcept; |
(since C++11) |
Constructs a new bad_cast
object with an implementation-defined null-terminated byte string which is accessible through what()
.
*this
and other
both have dynamic type std::bad_cast
then std::strcmp(what(), other.what()) == 0
. (since C++11)
Parameters
other | - | another exception object to copy |
std::bad_cast::operator=
bad_cast& operator=( const bad_cast& other ) throw(); |
(until C++11) | |
bad_cast& operator=( const bad_cast& other ) noexcept; |
(since C++11) |
Assigns the contents with those of other
. If *this
and other
both have dynamic type std::bad_cast
then std::strcmp(what(), other.what()) == 0
after assignment. (since C++11).
Parameters
other | - | another exception object to assign with |
Return value
*this
.
std::bad_cast::what
virtual const char* what() const throw(); |
(until C++11) | |
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 <typeinfo> struct Foo { virtual ~Foo() {} }; struct Bar { virtual ~Bar() {} }; int main() { Bar b; try { Foo& f = dynamic_cast<Foo&>(b); } catch(const std::bad_cast& e) { std::cout << e.what() << '\n'; } }
Possible output:
Bad dynamic cast
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