The CONST keyword on a subprocedure’s parameter indicates that the parameter value will not be changed by the subprocedure. This is
not just a nice way to communicate with the programmers who will call the procedure. It also offers performance benefits, because it allows the
compiler to produce more optimized code. Further, using CONST means that a field of a similar data type will automatically be converted
to the correct type and size for the parameter.
Noncompliant code example
D X S 15A INZ('ABC')
P SubProc1 B
D SubProc1 PI
D Parm1 15A // Noncompliant; read-only. Should be CONST
D Parm2 15A
/Free
X = Parm1;
Parm2 = X;
return;
/End-free
P SubProc1 E
Compliant solution
D X S 15A INZ('ABC')
P SubProc1 B
D SubProc1 PI
D Parm1 15A CONST
D Parm2 15A
/Free
X = Parm1;
Parm2 = X;
return;
/End-free
P SubProc1 E
