Init global variables at run-time

Can some one throw more light on this statement=> /* Init global variables at run-time, not as part of the declaration. * This is required to support init/de-init of the driver. Initialization * of globals as part of the declaration results in non-deterministic * behaviour since the value of the globals may be different on the * first time that the driver is initialized vs subsequent initializations. Thanks and Regards Sraddha