I have made frequent use of the CALL MISSING function, most commonly with numeric arrays, as in
array myvars {*} a1-a5 m1-m5;
call missing(of myvars{*});
But instead of re-setting to missing, I often (probably most of the time) would prefer to set all the variables to a zero (or to some other constant value), as in
array myvars {*} a1-a5 m1-m5;
call constant(0,of myvars{*});
call constant(0,of _numeric_);
And if the introduction of a user-specified constant is problematic, then just a CALL ZERO function would serve pretty well.
And less frequently needed, but useful if for no other reason than to parallel other function pairs, such as COALESCE/COALESCEC, it would be nice to have a call constant pair as well, i.e. CALL CONSTANT/CALL CONSTANTC, such that this is available.
array myvars {*} $ char1-char5;
call constantc('****',of myvars{*});
call constantc('****',of _character_);