Questions and answers

What is RTTI used for?

What is RTTI used for?

Run-time type information (RTTI) is a mechanism that allows the type of an object to be determined during program execution. RTTI was added to the C++ language because many vendors of class libraries were implementing this functionality themselves. This caused incompatibilities between libraries.

How does RTTI work in C++?

In C++ the RTTI is a mechanism, that exposes information about an object’s datatype during runtime. This feature can be available only when the class has at least one virtual function. It allows the type of an object to be determined when the program is executing. In the following example, the first code will not work.

Is RTTI a Typeid?

Typeid != RTTI. Just like dynamic_cast, the typeid does not always need to use RTTI mechanism to work correctly. If the argument of the typeid expression is non-polymorphic type, then no runtime check is performed.

Does C have RTTI?

In computer programming, run-time type information or run-time type identification (RTTI) is a feature of some programming languages (such as C++, Object Pascal, and Ada) that exposes information about an object’s data type at runtime.

Does dynamic_cast use RTTI?

RTTI (Run-time type Information) in C++ For example, dynamic_cast uses RTTI and following program fails with error “cannot dynamic_cast `b’ (of type `class B*’) to type `class D*’ (source type is not polymorphic) ” because there is no virtual function in the base class B.

Which type of class we can apply RTTI?

3. To which type of class, We can apply RTTI? Explanation: RTTI is available only for classes which are polymorphic, which means they have at least one virtual method.

What is difference between Static_cast and Dynamic_cast?

static_cast − This is used for the normal/ordinary type conversion. dynamic_cast −This cast is used for handling polymorphism. You only need to use it when you’re casting to a derived class. This is exclusively to be used in inheritence when you cast from base class to derived class.

Is Rtti slow?

tl;dr: RTTI in GCC uses negligible space and typeid(a) == typeid(b) is very fast, on many platforms (Linux, BSD and maybe embedded platforms, but not mingw32). If you know you’ll always be on a blessed platform, RTTI is very close to free.

How expensive is RTTI?

A while ago I measured the time costs for RTTI in the specific cases of MSVC and GCC for a 3ghz PowerPC. In the tests I ran (a fairly large C++ app with a deep class tree), each dynamic_cast<> cost between 0.8μs and 2μs, depending on whether it hit or missed.

Why is RTTI bad?

RTTI only works if your classes have a virtual table. If you have a virtual table you can implement virtual functions. The reason you should use virtual functions over a switch on the type of the object is that it works better with inheritance chains, and is less fragile when adding new classes.

Which type of program is recommended to include in TRY block?

2. Which type of program is recommended to include in try block? Explanation: While during dynamic memory allocation, Your system may not have sufficient resources to handle it, So it is better to use it inside the try block. 3.

Which of the following advantages we lose by using multiple inheritance?

3. Which of the following advantages we lose by using multiple inheritances? Explanation: The benefit of dynamic binding and polymorphism is that they help making the code easier to extend but by multiple inheritance it makes harder to track.

What does runtime type information ( RTTI ) mean?

Runtime Type Information is a mechanism that was build to expose information about a type at runtime. But from a reverse engineers point of view, it’s also a valuable information source for static analysis. In general, RTTI can mean information about type names, data-types or even memory structure.

What does access violation-no RTTI data mean?

When I pressed “Create HDL wrapper” , a tiny window popped up and said ” Access Violation – no RTTI data!” . I looked at the messages and it says ” [#UNDEF] Tcl Error in evaluating proc can_apply_rule : Access violation – no RTTI data!”.

Is there no RTTI data in autodesk community?

Access violation – no RTTI data! – Autodesk Community – Inventor Welcome to Autodesk’s Inventor Forums. Share your knowledge, ask questions, and explore popular Inventor topics. This page has been translated for your convenience with an automatic translation service.

When to use no RTTI data in compiler?

Usage Use –no_rtti_data to disable both source-level features and the generation of most RTTI data. Even if –no_rtti_data is set, RTTI data are generated for exceptions. Mode These options are effective only if the source language is C++.