std::bad_typeid
| Defined in header <typeinfo>
|
||
| class bad_typeid : public std::exception; |
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An exception of this type is thrown when a typeid operator is applied to a dereferenced null pointer value of a polymorphic type.
Inheritance diagram
Member functions
| (constructor) |
constructs a new bad_typeid object (public member function) |
| operator= |
replaces the bad_typeid object (public member function) |
| what |
returns the explanatory string (public member function) |
std::bad_typeid::bad_typeid
| (1) | ||
bad_typeid() throw(); |
(until C++11) | |
| bad_typeid() noexcept; |
(since C++11) | |
| (2) | ||
bad_typeid( const bad_typeid& other ) throw(); |
(until C++11) | |
| bad_typeid( const bad_typeid& other ) noexcept; |
(since C++11) | |
Constructs a new bad_typeid object with an implementation-defined null-terminated byte string which is accessible through what().
std::bad_typeid then std::strcmp(what(), other.what()) == 0.(since C++11)Parameters
| other | - | another exception object to copy |
std::bad_typeid::operator=
| bad_typeid& operator=( const bad_typeid& other ) throw(); |
(until C++11) | |
| bad_typeid& operator=( const bad_typeid& other ) noexcept; |
(since C++11) | |
Assigns the contents with those of other. If *this and other both have dynamic type std::bad_typeid 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_typeid::what
| virtual const char* what() const throw(); |
(until C++11) | |
virtual const char* what() const noexcept; |
(since C++11) (constexpr since C++26) |
|
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.
|
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) |
| [virtual] |
returns an explanatory string (virtual public member function of std::exception) |
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_constexpr_exceptions |
202411L |
(C++26) | constexpr for exception types |
Example
Possible output:
Attempted a typeid of NULL pointer!