Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
Export (0) Print
Expand All
Expand Minimize
Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here.

/GR (Enable Run-Time Type Information)

Adds code to check object types at run time.


When /GR is on, the compiler defines the _CPPRTTI preprocessor macro. In Visual C++ 2005, /GR is on by default. /GR- disables run-time type information.

Use /GR if your code uses dynamic_cast Operator or typeid. /GR does, however, cause the .rdata sections of your image to increase in size. If your code does not use dynamic_cast or typeid, using /GR- may produce a smaller image.

For more information on run-time type checking, see Run-Time Type Information in the C++ Language Reference.

To set this compiler option in the Visual Studio development environment

  1. Open the project's Property Pages dialog box. For details, see How to: Open Project Property Pages.

  2. Click the C/C++ folder.

  3. Click the Language property page.

  4. Modify the Enable Run-Time Type Info property.

To set this compiler option programmatically

Community Additions

© 2015 Microsoft