Re: Passing By Reference

[Scott Klement <klemscot@xxxxxxxxxxxx>]

This line is wrong:
    F1 = %replace('':F1:%scan(C1:F1):1);

It is setting all 32766 characters of F1.   This is a problem because F1
may not be that long, and therefore, it will be overwriting memory that
it should not be.

Also, the RETURN statement:

     Return F1;

This is copying 32766 bytes from the start of F1 to make a return value.
That's not good because you're reading from memory past the end of the F1
parameter if it's not the full size.

Not only that, but since F1 is passed by reference, it really doesn't
make much sense to use it as a return value.   You've already got the
result in the calling procedure... returning it makes another copy of
it as well.   If you are assigning that return value back to the same
variable, you'll cause some nasty problems.

So, here's what I'd do:

    1) Change the F1 = %replace() line to be %subst(F1:1:InLen) =
               %replace(etc).
    2) Remove the RETURN statement.
    3) Remove the return value from your Prototype (PR) statement
    4) Remove the return value from your Procedure Interface (PI)
               statement

See if that works...


On Mon, 25 Nov 2002, JJW wrote:

> Here's the code that has the problem with the pointer not
> set.
>
> H nomain
>
>
>   *
> --------------------------------------------------------------------
> H debug(*YES)
>
> H option(*SRCSTMT)
>
>   *
> --------------------------------------------------------------------
>   /COPY *libl/sanfords,elimpr
>
>   *
> --------------------------------------------------------------------
>   *     B E G I N    P R O C E D U R E
>
>   *
>
>
> P prREMOVE        B                   Export
>
>   *
> --------------------------------------------------------------------
> D prREMOVE        PI         32766    Opdesc
>
> D   F1                       32766    Options(*varsize)
>
> D   C1                           1    Const
>
>   *
> --------------------------------------------------------------------
> D CEEDOD          PR
> D   ParmNum                     10I 0 Const
> D                               10I 0
> D                               10I 0
> D                               10I 0
> D                               10I 0
> D                               10I 0
> D                               12A   Options(*omit)
>   * -------------------------------------------------
> D DataType        S             10I 0 Inz
> D DescInfo1       S             10I 0 Inz
> D DescInfo2       S             10I 0 Inz
> D DescType        S             10I 0 Inz
> D InLen           S             10I 0 Inz
>   * -------------------------------------------------
>
>   /free
>
>
>     CEEDOD(1:DescType:DataType:DescInfo1:DescInfo2:InLen:*omit);
>
>
>     If InLen <> *Zeros AND C1 <> *Blanks;
>
>
>
>        Dow (%scan(C1:F1) > *Zeros)  AND  (%scan(C1:F1) <=
> InLen);
>           F1 = %replace('':F1:%scan(C1:F1):1);
>
>        endDO;
>
>
>
>     endIF;
>
>
>
>     Return F1;
>
>
>
> /end-free
>
>
>
>   prREMOVE        E
>