typeid
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Category
Operators (C++), C++ Specific Keywords
Syntax
typeid(expression) typeid(type-name)
Description
You can use typeid to get run-time identification of types and expressions. A call to typeid returns a reference to an object of type const type_info. The returned object represents the type of the typeid operand.
If the typeid operand is a dereferenced pointer or a reference to a polymorphic type, typeid returns the dynamic type of the actual object pointed or referred to. If the operand is non-polymorphic, typeid returns an object that represents the static type.
You can use the typeid operator with fundamental data types as well as user-defined types.
When the typeid operand is a class object/reference, typeid returns the static rather than run-time type.
If the typeid operand is a dereferenced NULL pointer, the bad_typeid exception is thrown.