Re: Why would this statement fail?

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

I don't know why this statement fails on V4. My best guess is that the 
V4 level compilers incorrectly assume that the intermediate result is an 
unsigned number.  It's true that the output of the %scan() BIF is an 
unsigned number, but when you subtract 1 from it, the intermediate 
result SHOULD be a signed number (and it is in V5).   I can only guess 
that this is a bug in the older compilers that IBM fixed before V5R1 was 
released.

An easy workaround is to make the code look like this:

     c                   eval      pos = %scan('?': path)
     c                   eval      pos = pos - 1

That should achieve the exact same results, but since the subtraction is 
on a separate statement, the compiler should make a different decision 
about the intermediate result.


James Lampert wrote:
> Given that "path" is 32767A, and VARYING, and that POS is either 10I or 
> 29P 0, why would
>
>      eval      pos = %scan('?': path) - 1
>
> give an MCH1201 error when executed?
>
> Compiler is V4R2; OS is V4R4. Also fails under V4R5. Also fails if 
> "path" is 255A VARYING.