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| Passing a reference argument FROM a function |
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| goffinf |
 Posted: Mon Nov 19, 2007 9:00 am Post subject: Passing a reference argument FROM a function |
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Chevalier
Joined: 05 Nov 2005
Posts: 401
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I appreciate that variants of this question have been asked lots of times (and I've just spent quite a while reading most of them), but I can't seem to find a definitive answer for the question ... 'can I pass an updated REFERENCE argument back from a function' ?
For example (keeping things simple) I have tried this but the myRef variable does not appear to point to Environment.variables.someRef after the call (it still points to Environment) :-
-- call the function
DECLARE rc INTEGER;
DECLARE myRef REFERENCE TO Environment;
SET rc = getLocation(Environment, myRef);
CREATE FUNCTION getLocation(IN Environment REFERENCE, INOUT location REFERENCE) RETURNS INTEGER
BEGIN
CREATE FIELD Environment.variables.someRef;
DECLARE yourRef REFERENCE TO Environment.variables.someRef;
MOVE yourRef TO location;
RETURN 0;
END;
many thanks
Fraser. |
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| tleichen |
| Posted: Mon Nov 19, 2007 9:14 am Post subject: |
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Yatiri
Joined: 11 Apr 2005
Posts: 663
Location: Center of the USA
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This is an MQSeries forum; not a programming class. 
_________________
IBM Certified MQSeries Specialist
IBM Certified MQSeries Developer |
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| goffinf |
| Posted: Mon Nov 19, 2007 9:19 am Post subject: |
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Chevalier
Joined: 05 Nov 2005
Posts: 401
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| Perhaps I'm missing your point, this *is* an eSQL question which when I looked last was pretty much central to WBI ? |
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| mgk |
| Posted: Mon Nov 19, 2007 10:35 am Post subject: |
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Padawan
Joined: 31 Jul 2003
Posts: 1642
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Hi.
The simple answer to your question is yes.
| Quote: |
| The myRef variable does not appear to point to Environment.variables.someRef after the call |
.
Assuming that Environment.variables.someRef exists before you declared myRef to point it (as DECLAREing a ref to somewhere does not create elements) your problem would appear to be that you are not moving correctly, as your code:
| Code: |
| MOVE yourRef TO location; |
should be
| Code: |
| MOVE location TO yourRef; |
Regards,
_________________
MGK
The postings I make on this site are my own and don't necessarily represent IBM's positions, strategies or opinions. |
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| goffinf |
| Posted: Tue Nov 20, 2007 3:03 am Post subject: |
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Chevalier
Joined: 05 Nov 2005
Posts: 401
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Thanks for that [slightly embarrasing] spot.
For the benefit of everyone else, with the fix suggested, the 'location' argument reference *is* updated and means that from the main body of code you can use it, e.g. :-
SET myref.foo = 'bar';
has the effect of creating a child under Environment.variables.someRef called 'foo' with a value of 'bar'.
We find this useful because certain loactions in the MB global environment are used for specific data and are updatable via wrapper functions. However it is sometimes more practical (rather than create an arbitrary number of wrapper functions) for a developer to update data into these locations directly. However we still want the abstraction (we may decide to change the actual location in the future), so returning a reference as above proves to be useful.
Thanks for your help
Fraser. |
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