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| Author |
Interesting bugtrap
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| Robert Wagner 2004-07-15, 8:55 pm |
| I have a a called program that sends emails to employees. I want to enhance it
to send emails to outsiders, with the email address supplied by the calling
program. To avoid re-testing existing callers, I add an extra parameter not
supplied by existing callers. Existing programs should work exactly as they did
before the change.
The result is the new program works, but existing programs display "parm4
absent" and then abend with an address error. See whether you can figure out why
before scrolling down, where the answer is revealed.
WORKING-STORAGE SECTION.
01 EMAIL-IND PIC X(01).
LINKAGE SECTION.
01 USER_NAME PIC X(10).
01 EMAIL-SUBJECT PIC X(54).
01 EMAIL-BODY PIC X(1000).
01 EMAIL-TO PIC X(80).
PROCEDURE DIVISION USING
USER_NAME
EMAIL-SUBJECT
EMAIL-BODY
EMAIL-TO. *> this parm is optional, usually absent.
IF ADDRESS OF EMAIL-TO EQUAL TO NULL OR
EMAIL-TO EQUAL TO SPACES
MOVE 'N' TO EMAIL-IND
display 'parm4 absent'
ELSE
MOVE 'Y' TO EMAIL-IND
display 'parm4 present'
END-IF.
EXEC SQL EXECUTE
declare
smtp_recipient varchar2(80);
cursor email_cursor is
select EMAIL_ADDRESS from USERS
where USER_NAME =
rtrim(:USER_NAME, ' ');
begin
for email_rec in email_cursor loop
-- Pickup email address(s)
if :EMAIL-IND = 'N' then
smtp_recipient := email_rec.EMAIL_ADDRESS;
else
smtp_recipient := rtrim(:EMAIL-TO);
end if;
-- logic to send email snipped
end loop;
end;
END-EXEC.
GOBACK.
How can it abend when EMAIL-TO is never referenced? My first thought was that
PL/SQL was executing both sides of the IF in parallel, in multiple threads. The
correct answer is simpler and less esoteric. Here is the corrected version.
WORKING-STORAGE SECTION.
01 EMAIL-IND PIC X(01).
01 WS-EMAIL-TO PIC X(80).
LINKAGE SECTION.
01 USER_NAME PIC X(10).
01 EMAIL-SUBJECT PIC X(54).
01 EMAIL-BODY PIC X(1000).
01 EMAIL-TO PIC X(80).
PROCEDURE DIVISION USING
USER_NAME
EMAIL-SUBJECT
EMAIL-BODY
EMAIL-TO. *> this parm is optional, usually absent.
IF ADDRESS OF EMAIL-TO EQUAL TO NULL OR
EMAIL-TO EQUAL TO SPACES
MOVE 'N' TO EMAIL-IND
MOVE SPACES TO WS-EMAIL-TO
display 'parm4 absent'
ELSE
MOVE 'Y' TO EMAIL-IND
MOVE EMAIL-TO TO WS-EMAIL-TO
display 'parm4 present'
END-IF.
EXEC SQL EXECUTE
declare
smtp_recipient varchar2(80);
cursor email_cursor is
select EMAIL_ADDRESS from USERS
where USER_NAME =
rtrim(:USER_NAME);
begin
for email_rec in email_cursor loop
-- Pickup email address(s)
-- CAUTION: At execution time, preprocesser
-- code replaces host variables with values,
-- then does an EXECUTE IMMEDIATE on the
-- PL/SQL program. If EMAIL-TO has a null
-- pointer, that causes an abend, even
-- though EMAIL-TO will not be referenced.
if :EMAIL-IND = 'N' then
smtp_recipient := email_rec.EMAIL_ADDRESS;
else
smtp_recipient := rtrim(:WS-EMAIL-TO);
end if;
-- logic to send email snipped
end loop;
end;
END-EXEC.
GOBACK.
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| JerryMouse 2004-07-16, 3:55 am |
| Robert Wagner wrote:
> I have a a called program that sends emails to employees. I want to
> enhance it to send emails to outsiders, with the email address
> supplied by the calling program. To avoid re-testing existing
> callers, I add an extra parameter not supplied by existing callers.
> Existing programs should work exactly as they did before the change.
>
> The result is the new program works, but existing programs display
> "parm4 absent" and then abend with an address error. See whether you
> can figure out why before scrolling down, where the answer is
> revealed.
>
> WORKING-STORAGE SECTION.
[...]
The program doesn't use enough pointers?
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