CALL verb in COBOL/CICS programs?

shot makerr · New User Joined: 28 Apr 2008 Posts: 1 Location: Pune

Hi,
I don't have any exposure to CICS environment, so this question may sound silly, sorry for that. I could not get answers from anywhere, hence posting here.

We can use CALL verb in COBOL/CICS, however we dont get to see this. we only see this being handled by LINK/XCTL. why?
Is there any limit in using CALL in COBOL/CICS? like whether called module can have CICS instruction or not? whether this called module need to be registered in CIC control tables?
Can we relate STATIC and DYNAMIC with CALL,LINK and XCTL?

acevedo · Active User Joined: 11 May 2005 Posts: 344 Location: Spain

as far as I know Link and XCTL are dynamic.

you can force CALL dynamic using a working field with the name of the program to be called .

CALL w-nameofprogram USING copybook
CALL 'nameofprogram' USING copybook

in this point read for the DYNAM compiler option.

you can use CALL to invoke programs with CICS sentences...BUT take care as the DFH blocks are inserted in the Procedure division (by the CICS traductor) as: PROCEDURE DIVISION USING dfheiblk dfhcommarea and if not done properly the arguments could be misplaced...

hth

kalukakkad · New User Joined: 10 Mar 2005 Posts: 81

Some more points of using 'CALL' over 'LINK/XCTL'

1) 'Call' uses less number of instruction than 'LINK/XCTL', hence faster.

2) When using 'Call' in CICS, the CICS TRACE will not show any entries (drawback),whereas LINK/XCTL will have an entry. Useful in debugging.

3) LINK/XCTL requires PPT entry for the called program. But if the called program does not have any CICS instructions, there is no need for a PPT entry and you use 'CALL'.

acevedo · Active User Joined: 11 May 2005 Posts: 344 Location: Spain

and...... beware of using EXEC CICS RETURN in a called program when the caller has invoke it using CALL instead of LINK.

CICS Guy · Posted: Wed Apr 30, 2008 8:06 pm

Bill O'Boyle · Posted: Wed Apr 30, 2008 8:47 pm

Some cautionary observations -

If the Caller is defined as THREADSAFE in the PPT, the called program better be THREADSAFE as well. Otherwise, you're going to have some "opportunities".

If the Caller is accessing the Called program "STATICALLY", then then Caller needs to pass their own WS as a parameter to the Called program and allow the Called program to use the Caller's WS as its own (defined to LINKAGE). This is especially true with THREADSAFE but it can also rear its ugly head in a non-THREADSAFE run-unit.

One final note is that the CALL verb does not invoke MVS services, even though you've specified the called sub-program in a variable, but it's not DYNAMIC. CICS uses it's own method to locate the target sub-program via a PPT lookup.

COBOL/CICS programs must always specify the NODYNAM compile option.

Regards,

Bill