ILE C/C++ Programmer's Guide


The RTTI Language Extension

The C++ language supports both the re-use of code and the building of programs from parts. There might be incompatibilities between RTTI mechanisms used internally by various C++ libraries. The RTTI language extension resolves those incompatibilities.

C++ language support for RTTI include:

dynamic_cast operator
This operator combines type-checking and casting in one operation. It checks whether the requested cast is valid, and performs the cast only if it is valid.

typeid operator
This operator returns the run-time type of an object. If the operand provided to the typeid operator is the name of a type, the operator returns a type_info object that identifies it. If the operand provided is an expression, typeid returns the type of the object that the expression denotes.

type_info class
This class describes the RTTI available, and is used to define the type returned by the typeid operator. This class provides to users the possibility of shaping and extending RTTI to suit their own needs. This ability is of most interest to implementers of object I/O systems such as debuggers or database systems.


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