Re: Clever UNIX/C Constructs

[boldt@xxxxxxxxxx]

Jon wrote:
>Hans wrote:
> >> Oh yeah, also performance.  Consider the statements:
> >>       Totals(FindItem('xyz')) += incr;
> >>       Totals(FindItem('xyz')) = Totals(FindItem('xyz')) + incr;
>
>Isn't that more of a lack of optimization in the compiler and/or
optimizing
>translator than a performance issue Hans?

No.  Regardless of optimization, there are two procedure calls in the
second statement.  If the compiler or optimizer knew for sure that
there were no side effects in the procedure being called, it could
optimize.  But in RPG we can't know that unless we examine the called
procedure, which is clearly impractical for procedures that haven't
been written yet.  Languages that can optimize that case normally have
some keyword to indicate that the procedure has no side-effects.

Cheers!  Hans

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

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