IBM AS/400 manual Interlanguage, Calling Considerations

Table

11.

RPG Parameter Passing Methods

Passing

By

Reference

ILE

RPG

–

prototype

D

proc

PR

D

parm

1A

C

CALLP proc(fld)

ILE

C

void proc(char *parm);

proc(&fld);

ILE

COBOL

CALL PROCEDURE "PROC" USING BY REFERENCE PARM

RPG

–

non-prototyped

C

CALL

'PROC'

C

PARM

FLD

ILE

CL

CALL PROC (&FLD)

Passing

By

Value

ILE

RPG

–

prototype

D

proc

PR

D

parm

1A

VALUE

C

CALLP proc('a')

ILE

C

void proc(char parm);

proc('a');

ILE

COBOL

CALL PROCEDURE "PROC" USING BY VALUE PARM

RPG – non-prototyped

N/A

ILE

CL

N/A

Passing

By Read-Only Reference

ILE

RPG

–

prototype

D

proc

PR

D

parm

1A

CONST

C

CALLP proc(fld)

ILE

C

void proc(const char *parm);

proc(&fld);

ILE

COBOL

N/A

1

RPG – non-prototyped

N/A

ILE

CL

N/A

Notes:

1. Do

not

confuse passing

by read-only reference

with COBOL's

passing

BY

CONTENT. In RPG

terms, to

pass

Fld1 by

content,

you

would

code:

C

PARM

Fld1

TEMP

Fld1

is

protected

from

being

changed,

but TEMP

is

not.

There

is no

expe

the

parameter

will

not

be changed.

For information on the data types supported by different HLLs, consul priate language manual.

Interlanguage	Calling Considerations
	1. When returning a 1-byte character value to or							from ILE C or I
	returned	value must	be	declared		in a	special	way.
	For ILE CL, declare the returned value						as a 2-byte character a
	%SUBSTRING	to obtain	the	actual	returned value.
	DCL &RET2 TYPE(*CHAR) LEN(2)
	DCL &RET1 TYPE(*CHAR) LEN(1)
	CALLPRC RPGPROC RTNVAL(&RET2)
	CHGVAR &RET1 VALUE(%SUBSTRING(&RET2 1 1))
				Chapter	10.	Calling	Programs and	Procedures147