I have been using Raisonance "C", but the example of programming should be the same in Keil.

This is not a safe assumption at all!

Dealing with with such detailed target-specifics as XDATA, PDATA, etc is way beyond the scope of ANSI 'C' - therefore any such extensions provided by any particular implementation must be considered to be non-portable!

Of course, one would hope that all 'C' compilers targetted at the 8051 would provide some way to achieve this, and they might even provide similar ways, but you cannot assume that they will provide precisely the same way!