Re: [Re: RPGILE V4.3 Gotcha]

[boldt@xxxxxxxxxx]

Peter wrote:
>> You could always stick to the traditional ADD, SUB, MULT, etc
>> opcodes.  But since the default behavior of those is to
>> truncate results instead of failing on numeric overflow,
>> those opcodes are the real unsafe ones!
>
>It depends upon what you're trying to accomplish. Imagine if MULT always
>failed on overflow. How many programs are out there that used MULT 100.0001
>or MULT 10000.01 to flip a date around? In one sense, any opcode is "unsafe"
>if you don't understand what it's doing. I remember waaaay back when
>learning RPG after knowing COBOL, and expecting MOVE to MOVEL with Padding!

Ah, another FAQ!  A long time ago, I did a comparison
comparing the performance of the old MULT 100.0001 trick.
I found that using MULT was about 100 to 150 times slower
than doing the date conversion using a couple of moves.

I have yet to find a good example where using the decimal
truncation behavior of the old opcodes provides any
advantage.  Since numeric overflow is almost always a
programming error, to me it makes little sense compiling
without TRUNCNBR(*NO).

Cheers!  Hans

Hans Boldt, ILE RPG Development, IBM Toronto Lab, boldt@ca.ibm.com


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