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/GR (Enable Run-Time Type Information)
Updated: September 2008
Adds code to check object types at run time.
When /GR is on, the compiler defines the _CPPRTTI preprocessor macro. By default, /GR is on in Visual C++ 2005. /GR- disables run-time type information.
Use /GR if the compiler cannot statically resolve an object type in your code. You usually need the /GR option when your code uses dynamic_cast Operator or typeid. However, /GR increases the size of the .rdata sections of your image. If your code does not use dynamic_cast or typeid, /GR- may produce a smaller image.
For more information about 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
Open the project's Property Pages dialog box. For details, see How to: Open Project Property Pages.
Click the C/C++ folder.
Click the Language property page.
Modify the Enable Run-Time Type Info property.
To set this compiler option programmatically