Dynamic storage management
Vieweg+Teubner eBooks · 2009
The language PL/I defines different storage classes depending upon the life span and access method of the variables. So far we have become acquainted with the two classes automatic and static . They only differ in life span: automatic variables exist as long as the block is active in which they are declared, and static variables exist during the run time of the entire program. This corresponds also, of course, to the kind of initialization: static variables get their initial value only once (apart from fetch ), and automatic variables with each entrance into “their” block. For repetition it should be mentioned that in principle parameters represent their own storage class. They are neither static nor automatic , as storage is made available to them in the calling program in each case, whether they are static or automatic