Re: Assigning a value to a DDS varlen defined field

[Stuart Rowe <rowestu@xxxxxxxxx>]

If you always want this data to be first,

XCVAR1 = 'false' + XCVAR1;

ought to work as it's defined as varying.

Otherwise, as John and others pointed out, you need to be sure to tell RPG
that you do have enough room for the data -- via the length.  Yes, there's
always enough room allocated, but RPG won't use more than %len() characters
of it.

There is good info in the RPGLE reference about when the length is set, how
it is set, and what heppens to the data when the length is set.

Stu



On Mon, Feb 27, 2012 at 13:46, Loek Maartens <l.maartens@xxxxxxxxx> wrote:

> Hello group,
>
> I have a field named XCVAR1 in a database file with a size of  150 bytes
> defined with the DDS keyword VARLEN (no size specified).
>
> I understand that this field initially has a length of zero.
>
> Just setting the field XCVAR1 works;
>
> XCVAR1 = 'false' ;
>
> but there might be other values in this VARLEN defined field that I should
> leave intact (and at the same offset) when they were set by other programs.
>
> When trying to set the field to a value like:
>
> %subst(XCVAR1:1:5) = 'false';
>
> the programs throws an error complaining about invalid field size.
>
> If I first set the XCVAR1 field size like;
>
> if %len(XCVAR1) < 5;
> %len(XCVAR1) = 5;
> endif;
>
> all is well.
>
> Should the compiler not just set the length of XCVAR1 to 5 when I assign
> the
> value 'false' if the XCVAR1 length is less then the value I want to set
> using the %subst function or can someone explain why not?
>
>
> Kind regards,
>
> Loek Maartens.
>
>
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