RE: Varying(4) bug ?

Dennis,



In the manual it says...



When the keyword CONST is specified, the compiler may copy the parameter to a

temporary and pass the address of the temporary. Some conditions that would

cause this are: the passed parameter is an expression or the passed parameter has a

different format.



... so I expected that Varying and Varying(4) would be a "different format" (just like for example a short int and int are both integers).



While the Value keyword solves my issue, it is not ideal for performance and I don't see what difference or efficiency the Options(*String) brings ?



Isn't it so that when I now pass a Varying(2) of 100 bytes to a procedure accepting a Varying(2) of 64K with Const parameter that it does NOT make a temporary copy of the 100 bytes... which is an advantage I loose with the Value keyword.



Kind regards,

Paul



________________________________
From: rpg400-l-bounces@xxxxxxxxxxxx [rpg400-l-bounces@xxxxxxxxxxxx] on behalf of Dennis Lovelady [iseries@xxxxxxxxxxxx]
Sent: Wednesday, April 13, 2011 12:36
To: 'RPG programming on the IBM i / System i'
Subject: RE: Varying(4) bug ?

No, but VALUE will. Remember, with CONST, you're just passing an address.
With value, the variable will be converted if necessary, and the address of
the converted data is passed.

For efficiency, you might want VALUE OPTIONS(*STRING).

Dennis Lovelady
http://www.linkedin.com/in/dennislovelady
--
"I'd like to thank my parents and my mother and father."
-- golfer Greg Norman, accepting an award

I'm introducing Varying(4) into my programs as I need to handle more
data, but I'm experiencing something strange.



I have a procedure that accepts a Varying(4) which is defined with the
Const keyword. If I now call this procedure, passing a normal
Varying... the first two bytes of the string itself are dumped in
position 3 and 4 of the Varying(4) field ? See dump data below, ie.
the "He" or x'C885' gets into byte 3 and 4 ?



Shouldn't "Const" not solve this issue ?



Example:



H DftActGrp(*No) ActGrp(*Caller)

DMyProc PR 100 Varying(4)
D Var4 100 Varying(4) Const

Ds S 100 Varying

/free
s = 'Hello world.';
s = MyProc(s);

*INLR = *On;
Return;
/end-free
**********************************
* MyProc *
**********************************
PMyProc B Export

DMyProc PI 100 Varying(4)

D Var4 100 Varying(4) Const
**********************************
* Main *
**********************************
/free

// Dump 000CC885 93939640 A6969993 844B0000 - ..Hello world...
Return Var4;
/end-free
P E


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