Q. I read your tip about using CALLP with a variable program name. I want to do something similar, but with procedures. I want a program to choose one from among several different possible procedures to run, depending upon the contents of a database field. Is there a way to do this with CALLP?

A. Sort of. The procedure cannot be a variable. Your program will need a prototype for every possible procedure. You'll also need a prototype to be associated with a procedure pointer. Then use the %PADDR function to assign a storage location to the procedure pointer. Here's an example:

  // Possible procedures to call
D Addcust         PR
D                                5U 0 Value
D Updcust         PR
D                                5U 0 Value
D Delcust         PR
D                                5U 0 Value

  // Prototype for generic procedure
D Process         PR                  Extproc(Processptr)
D                                5U 0 Value

  // Pointer to hold procedure address
D Processptr      S               *   Procptr

D Action          S              1    Inz('A')
D Parameter       S              5U 0

 /Free
  Select;     // Assign appropriate procedure address to pointer
    When Action = 'A';
      Processptr = %Paddr(Addcust);
    When Action = 'U';
      Processptr = %Paddr(Updcust);
    When Action = 'D';
      Processptr = %Paddr(Delcust);
  Endsl;

  Process(Parameter);     // Call appropriate procedure
 /End-free

The prototype for each procedure must be consistent with the prototype associated with the procedure pointer; that is, they must accept the same parameters. But you can include the OPTIONS(*NOPASS) and/or OPTIONS(*OMIT) keywords to make some parameters optional or omissible.