Still it would depend on whether your rtl is statically or dynamically linked. If you have a dynamically linked rtl then another application using the same compiler, highly likely, could replace the rtl with a newer version. Admittedly the random number generator is highly unlikely to change. Even in your own application you may need to distribute a newer version of the rtl to fix a problem not of your own making. So most likely the best is to copy the source for the rtl routine and just call it if you want to be absolutely sure it doesn''t change.