what is the token between class and class-name

[Erin100280]

Example:
class _OgreExport DataStream : public StreamAlloc

Trying to find out what '_OgreExport' is/does in this case.

[bartoli]

It must be a macro for when ogre is used as a DLL, set to declspec(dllexport) or __declspec(dllimport) depending if the header file is used in the ogre DLL or in your program that uses ogre