.-NONULLPTR-. >>-RTCHECK--(--+-NULLPTR---+--)--------------------------------><
Under the RTCHECK(NULLPTR) option, extra code is generated to force the ERROR condition to be raised if a null pointer, that is, a pointer equal to SYSNULL(), is dereferenced (that is, if the pointer is used to change or obtain the value of a variable).
Using the RTCHECK(NONULLPTR) option, no such code will be generated.