Run-time type information

From Free net encyclopedia

Runtime Type Information (RunTime Type Identification) is information about an object's datatype that is set into memory at runtime.

Run Time Type Information is a computer programming term used to identify that a given language has the ability to determine the type of a program's object/variable at runtime.

Although available in most computer languages, RTTI, as a term, is typically used in relation to C++. In order for the dynamic_cast<> operation to work in C++, RTTI must be enabled.

An instance where RTTI is used is illustrated below:

class base {
};

class derived : public base {
public:
 int compare(derived &ref);
};

int my_comparison_method_for_generic_sort(base &ref1, base &ref2)
{
 derived d = dynamic_cast<derived &>(ref1); // rtti used here
 // rtti enables the process to throw a bad_cast exception
 // if the cast is not successful
 return d.compare(dynamic_cast<derived &>(ref2));
}

[[Category:C++]]de:RTTI fr:Run-time type information it:RTTI pl:RTTI ru:Тип данных#Динамическая идентификация типа данных