Parameter passing in COBOL

[Stephen Daddona]

I would like to do the following:

01 t_accpornam pic x(255) value spaces.

procedure division
giving tt_accpornam.

But, COBOL doesn't allow it:

giving tt_accpornam.
...........^
%COBOL-F-OPDGIVING, Operand must be a COMP data-name with 18 digits or less and
no scaling positions, COMP-1, or COMP-2
at line number 37 in file DISK$DKB100:[GET_TT_ACCPORNAM]GETTTACCPORNAM.COB;65

Is there any way that I pass "back" a pic x(255) data item?


Thanks in advance!

[John Reagan]

You need an argument to the routine by using a LINKAGE section and a USING clause. The caller will have to pass in the address of a buffer to fill.

[Stephen Daddona]

Do you have an example of doing that? I'm trying some stuff but not having much luck. I keep getting an access violation.

[Richard J Maher · Accepted solution]

Hi Graig

This one returns a VARCHAR, but does pretty much what you want (I think?) Somewhere in the procedure calling standard you find the bit about the first parameter being the non-integer return mechanism for functions.

create function ef_get_user_dir (in char(32) by descriptor)
returns varchar(94) by reference
language sql
;
external name ef_get_user_dir
location 'maher$user' with all logical_name translation
language cobol
general parameter style variant
comment is 'Get UAF device and directory info for user'
BIND ON CLIENT SITE
bind scope connect
;


linkage section.
*
01 username_desc pic x(8).
*
01 out_dir.
03 out_dir_len pic 9(4) comp.
03 out_dir_text pic x(94).
*
procedure division
using out_dir,
username_desc.
00.

Cheers Richard Maher

[John Gillings]

Craig,

Something like this:

IDENTIFICATION DIVISION.
PROGRAM-ID GetAccpornam.
...
LINKAGE SECTION.
01 tt_accpornam PIC X(255).
...
PROCEDURE DIVISION USING tt_accpornam.
...

MOVE whatever TO tt_accpornam.
...
EXIT PROGRAM.


(caller)

01 ACCPORNAM PIC X(255).

PROCEDURE DIVISION
...
CALL "GetAccpornam" USING ACCPORNAM.


The reason your example doesn't work is the OpenVMS calling standard only allows scalar objects to be returned as function results. Maximum size is 64 bits. Larger objects can only be returned via arguments.

(note that you could return a pointer to a string, but that's a bit cumbersome in COBOL and it raises issues of ownership and lifetime of the string storage).

[Stephen Daddona]

That should get me going down the YBR (Yellow Brick Road), since my ultimate goal was to get this COBOL program to pass the process's TT_ACCPORNAM back to an Rdb function.


Thanks!

[Stephen Daddona]

I'll be trying the suggestions ASAP!