Re: %Diff question

[Simon Coulter <shc@xxxxxxxxxxxxxxxxx>]

On 17/01/2008, at 5:43 AM, GKern@xxxxxxxxxxxxxxxx wrote:

> The infocenter states the following for %Diff:
>
> "The result is rounded down, with any remainder discarded. For  
> example, 61
> minutes is equal to 1 hour, and 59 minutes is equal to 0 hours."

That only applies when asking for the duration in the next higher  
level. If the duration is actually 61 minutes but you specify *HOURS  
you'll get 1 as the result. If 59 minutes you'll get 0 as the result.

This behaviour is explained in the 'Date Operations' section of the  
ILE RPG Language Reference.

> I have the following statement in a program where cur_time is  
> 12:38:15 and
> last_time is 11:38:15.
>
>
>      C                IF             %Diff 
> (Cur_Time:Last_Time:*Minutes) >
> 60
>
> Using the interpretation from the infocenter cited above, does that  
> mean
> that the %Diff would be 1 *Hour instead of 60 *Minutes?

No, because you requested the duration in *MINUTES. The result of  
this calculation given the times shown is 60.

> The reason I ask is that for some reason the code that should execute
> never does and therefore there must be something wrong with that  
> condition
> as coded

When in doubt write some test code to verify the behaviour:

 H TIMFMT(*HMS)

 D cur_time        S               T    INZ(T'12:39:15')
 D last_time       S               T    INZ(T'11:38:15')

 C                   IF        %Diff(Cur_Time:Last_Time:*Minutes) > 60
 C     'diff > 60'   DSPLY
 C                   ELSE
 C     'diff <= 60'  DSPLY
 C                   ENDIF

 C                   SETON                                        LR

gives 'diff > 60' as the output. This is exactly as expected.

> (and I don't know how to or if I can view the value of %Diff).

You can't view the result of %DIFF with this code. However %DIFF  
simply returns a numeric result so assign it to a variable and then  
you can examine it.

 C                   EVAL      RESULT = %Diff 
(Cur_Time:Last_Time:*Minutes)
 C                   IF        RESULT > 60

Note: In RPG there is no such thing as a 'duration data type' as  
stated by another responder. A duration is just a number and any RPG  
numeric data type is valid as long as it is large enough to hold the  
result.

> Could it be that the compiler is rounding up to 1 hour and therefore
> minutes is never greater than 60?

No.

> Or (in other words) is >60 a valid value for use with *Minutes?

Yes.

> Comments?

I suggest you read the section on Date Operations.

Regards,
Simon Coulter.
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