Re: [spam] Re: Why you shouldn't be afraid to use VARCHAR in RPGLE

Hi Brian,

Marco is absolutely right - of course I-specs are compiled AFTER D-specs - so if the %LEN in a D-spec is referencing an I-spec, it could not work. 

I finally had the time to try all this on PUB400 - so this will work:

  dcl-f myFile disk usage(*input);                    // the original file
  dcl-ds myType likerec(myFileR) template;  // a template from the record format
  dcl-s vc varchar(%len(myType.field)) inz;   // a field length derieved from the template

Of course you can also create the template directly with EXTNAME(...).

The template data structure doesn't use any Space in your program - it only defines a "type" that can be referenced to define other fields or data structures.

Sorry for causing some irritation - in fact I haven't thought about the compile sequence of the specifications. Our team also tends to have a "typeTableName" data structure template for nearly every database table, and we use those intensively.

HTH
Daniel


> Am 06.12.2025 um 16:27 schrieb Brian Parkins <[email protected]>:
> You might like to test it your examples, Daniel. I cannot get them to compile unless I code:
> 
> dcl-c #LEN Const(200);
> dcl-s w_address1 varchar(#LEN) inz;
> 
> - which doesn't satisfy Doug's request. (The wording in the manual is misleading.)
> 
> Brian.
> 
> On 06/12/2025 03:12, Daniel Gross wrote:
>> AFAIK - I might have to test it - this should be possible:
>> 
>>   dcl-s w_address1 varchar(%len(phaddress1)) inz;
>> 
>> At least it should be possible to define a constant and use this to define your varchar variable:
>> 
>>   dcl-c #LEN %len(phaddress1);
>>   dcl-s w_address1 varchar(#LEN) inz;
>> 
>> As long as the expression value is resolvable at compile time. But I'm pretty sure, that also the first form should work.
>> 
>> -> https://www.ibm.com/docs/en/i/7.6.0?topic=length-len-used-its-value
>> 
>> And you can also use %LEN to get the maximum size of a VARCHAR variable, simply use:
>> 
>>      %len(varchar_variable:*max)
>> 
>> -> https://www.ibm.com/docs/en/i/7.6.0?topic=lgsl-len-used-get-maximum-length-varying-length-expressions
>> 
>> But when %LEN is used in definition statement, it always returns the maximum length of variable length fields like VARCHAR. So it should also work the other way around:
>> 
>>   dcl-s x_address1 char(%len(w_address1)) inz;
>> 
>> HTH
>> Daniel
>> 
>> 
>>> Am 06.12.2025 um 03:41 schrieb Jon Paris <[email protected]>:
>>> Not quite, Charles.  $SIZE returns the storage required to hold the field - it's capacity will be 2 or 4 less than that due to the storage used by the length.
>>> So:
>>> Dcl-S  myVarLen  Varchar(200) Inz;  // %Len = 0, %Size = 202 bytes.
>>> Jon Paris
>>> [email protected]
>>>> On Dec 5, 2025, at 6:08 PM, Charles Wilt <[email protected]> wrote:
>>>> LIKE should pick up the both the type and size...
>>>> dcl-s w_address1 like(phaddress1);
>>>> note: %len() on a varchar is always the length of the current value.  The
>>>> max size is retrieved using %size().
>>>> HTH,
>>>> Charles
>>>>> On Fri, Dec 5, 2025 at 3:28 PM DEnglander--- via RPG400-L <
>>>>> [email protected]> wrote:
>>>>> Does anyone know how to do something like this:
>>>>> I would like to define a %TRIMmed disk field that is CHAR(200)
>>>>> [PHADDRESS1] as a VARCHAR and eliminate the %TRIMs.
>>>>> So as not to hardcode the size of the VARCHAR, can I define it as VARCHAR
>>>>> but based on the length of the CHAR(200) field? Something like:
>>>>> dcl-s   w_address1      varchar(%len(phaddress1));
>>>>> Can that be done?
>>>>> Thank you,
>>>>> Doug
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