Home > C++, VC++ > __declspec( novtable )

__declspec( novtable )

If a class is not meant to be intanstiated directly, using __declspec( novtable ) will help in reducing size of code generated for the class.

MSDN says this:

This form of _declspec can be applied to any class declaration, but should only be applied to pure interface classes, that is classes that will never be instantiated on their own. The _declspec stops the compiler from generating code to initialize the vfptr in the constructor(s) and destructor of the class. In many cases, this removes the only references to the vtable that are associated with the class and, thus, the linker will remove it. Using this form of _declspec can result in a significant reduction in code size.

Eg:

class _declspec( novtable ) SomeAbstractClass
{
  public:
    SomeAbstractClass(){}
    virtual bool SomeAbstractMethod() = 0;
}
Advertisements
  1. No comments yet.
  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: