std::bad_typeid
Defined in header <typeinfo> |
||
---|---|---|
class bad_typeid : public std::exception; |
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()
.
*this
and other
both have dynamic type 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) |
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 S { // The type has to be polymorphic virtual void f(); }; int main() { S* p = nullptr; try { std::cout << typeid(*p).name() << '\n'; } catch(const std::bad_typeid& e) { std::cout << e.what() << '\n'; } }
Possible output:
Attempted a typeid of NULL pointer!
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