IBM AS/400 Multiple Procedures Module, Prototype for procedure FmtCust Note the PR on definition

Multiple Procedures Module

¹ The number and nature of the parameters

¹ Which parameters must be passed, and which are optionally passed

¹ Whether operational descriptors are passed (for a procedure)

¹	The data type of the return value,		if	any (for a procedure)
The	prototype	is used by the compiler	to	call the program or	proce
and	to ensure	that the caller passes	the	correct parameters.	Figure

prototype for a procedure FmtCust, which formats various fields of a readable form. It has two output parameters.

*Prototype for procedure FmtCust (Note the PR on definition

*specification.) It has two output parameters.

D FmtCust		PR
D	Name	100A
D	Address	100A
Figure	13. Prototype for FmtCust Procedure

To produce the formatted output fields, FmtCust calls a procedure Num NumToChar has a numeric input parameter that is passed by value, and character field. Figure 14 shows the prototype for NumToChar.

*Prototype for procedure NumToChar

*The returned value is a character field of length 31.

D NumToChar PR 31A

*The input parameter is packed with 30 digits and 0 decima￿l

*positions, passed by value.

D	NUMPARM	30P 0 VALUE
Figure	14. Prototype for NumToChar Procedure

If the program or procedure is prototyped, you call it with CALLP o expression if you want to use the return value. You pass parameter follows the name of the prototype,namefor(parm1example,: parm2. : ...)

Figure 15 shows			a call to FmtCust. Note that the			names	of	the	output
shown	above	in	Figure 13,	do not	match those in	the	call	statement.
eter	names	in	a prototype	are	for documentation	purposes		only.	The

serves todescribethe attributes of the call interface. The actual de

parameters	takes place	inside the procedure itself.
C	CALLP	FmtCust(RPTNAME : RPTADDR)
Figure 15.	Calling the FmtCust Procedure

Using prototyped calls you can call (with the same syntax):

¹	Programs that		are	on	the	system at run time
¹	Exported	procedures			in other modules or service programs that are
	the same	program		or	service program
¹	Subprocedures		in	the	same	module

Chapter 4. Creating an Application Using Multiple35 Procedures