A question on preprocessor

Hi
I read somewhere that the keywords signal and slot(when used in class definition)will be translated to pure c++ by preprocessor.Is it a Qt defined(modified)C++ preprocessor?
thanks

The words signal and slot are first processed by the standard C++ preprocessor

Code:

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#   define slots
#   define signals protected

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(from src/corelib/kernel/qobjectdefs.h)

and also by moc, which will generate moc_*.cpp-files with the added functionality