varying keyword

[pagenbeast]

Hello All,

I have a input/output parameter defined as 25000 byte length. I'm not alway going to be populating the field with this much bytes so I was wondering if I could use the VARYING keyword to only pass back the actual values #bytes back to the calling program (or web application).

Never used the VARYING keyword before...is this the purpose of the VARYING keyword?

Please advise.

Thanks,

Pagen

[RPGnoobie]

Re: varying keyword

If you're only wanting to pass by value, just use the VALUE keyword.

[pagenbeast]

Re: varying keyword

The field is defined with a EXTPGM prototype and doesn't allow the value keyword.

[pramendra]

Re: varying keyword

Yeah!!! you can use variying keyword..

you can use options(*varsize) with string it will work.

be sure you can not pass longer string than defined.



Pramendra Pandeya

[pagenbeast]

Re: varying keyword

Thanks RPGnoobie and Pramendra for the help. I'll probably try the OPTIONS(*varsize) and the VARYING keywords and see what I get.

Thanks again.

Pagen

[tomholden]

Re: varying keyword

just a friendly FYI. if you use options(varsize) and a non-varying field make sure you don't access more characters than you pass in. if you do you will corrupt (overwrite/retrieve) data that may or may not belong to your program/process and can cause some severely undesired results!!!

[pagenbeast]

Re: varying keyword

Tahnks Tom,

The field is an output parameter, if I initialize with blank prior to inializing with the needed value, would this fix the issue you mentioned previously?

Please advise.

Thanks.

Pagen

[MichaelCatalani]

Re: varying keyword

Hello All,

I have a input/output parameter defined as 25000 byte length. I'm not alway going to be populating the field with this much bytes so I was wondering if I could use the VARYING keyword to only pass back the actual values #bytes back to the calling program (or web application).

Never used the VARYING keyword before...is this the purpose of the VARYING keyword?

Please advise.

Thanks,

Pagen

Any field that is longer than 100 bytes or so should be varying. A 25K byte field should absolutely be varying. When you build the contents of this field, you are likely having to trim the field several times. Basically, this requires the program to start at byte 25,000 and work backwards until it finds the first non-blank character. So if there is little data in that field, the program will have to do a lot of work to trim it.

Varying fields don't have to do this. By their design, they know exactly where the end of the field is at all times, so the overhead of trimming isn't required. Also, other bifs such as %scan are faster, because it doesn't have to scan all 25,000 bytes. It only has to scan until it reaches the end of the data in that field.


The keyword options(*varsize) is a totally different animal and shouldn't be confused with varying length fields. *varsize tells the program that a parameter is allowed to be passed with a shorter length than that specified in the prototype/interface.

In your case, I would simply change the field to varying, and then make sure that the prototypes and procedure interfaces that you are passing this field to are also changed to varying. As long as you are always passing a 25,000 varying field, you dont have to worry about options(*varsize).

[pramendra]

Re: varying keyword

Difference between varying and option(*varsize)

D myname        s            100A   VARYING
C                   eval      myString = 'PRAMENDRA PANDEYA'

In this example, the variable is declared as varying. It's true, I still coded "100A", but now that number specifies the maximum length of the string. The actual length can vary. In this example, myname only gets assigned the 17 characters. No blanks are added to the end.

On the other way option(*varsize)

*VARSIZE is an option that may be specified in the OPTIONS D-spec keyword. It has nothing to do with the data type of the variable. All it does is disable the compiler's validity checking of the length.

there is example here hope it helps....
http://http://forums.systeminetwork....ad.php?t=49845

Pramendra Pandeya

[tomholden]

Re: varying keyword

for a better description of what i'm talking about check out slides 36-38 in this powerpoint tommyholden.com

[pagenbeast]

Re: varying keyword

By reading all responses, it sounds like the VARYING keyword is the preferred method to use.

Thanks again to all that replied.

Pagen