Re: Global or static variables in RPG external UDTF program

[Robert Rogerson <rrogerson@xxxxxxxxxxx>]

Hi Darren, I'm kinda guessing, but I'm wondering if you should set idx1 
to zero when call_open.  Keep the variable static so it retains it's 
value between calls.

It almost sounds like the variable is only being initialized when you 
first call the function.  Could this be that the function is SQL and 
therefore runs in the DFTACTGRP?  And in my understanding the static 
variable would retain it's value until the end of the activation group.  
And the DFTACTGRP woldn't end until you signoff...

Like I said, I'm just guessing...

Rob


On 11/8/2016 2:49 PM, Darren Strong wrote:
> I'm coding an RPG program that extracts data from a list API.  In this
> case, its QZLSLSTI to list share names on the system.
>
> I'm very new to this, so I'm following an example where the author placed
> all functions in an exported sub-procedure. His example used a file, so its
> somewhat simpler than what I'd like to do. A UDTF function is called once
> for the open, and then multiple times for the fetch, and one more time for
> the close. Since I'm processing a list API, pointer data to the user space
> is created during the "open", and then paged through using pointer offsets
> during the "fetch", and finally the user space is deleted during the
> "close".
>
> I'm having some trouble with variables between the calls, I think. Since
> everything is under the subprocedure definition, nothing is a global
> variable or static.  The pointers to the user space seem to need to be
> "static", so I made them static, but my offset index counter does not seem
> to need to be static for some reason.  Sometimes if I execute the SQL to
> read from this table more than once, I get no results, which I'm assuming
> is because of static variable not being reset, because if I sign out and
> back in, things work again.
>
> How should I be managing the memory when coding this API to SQL UDTF?
>
>
>         ctl-opt option(*srcstmt:*nodebugio) nomain;
>
>         dcl-proc LSTSHR1 export;
>
>         dcl-ds USH likeds(QUSH0100_t) based(USH_P);
>         dcl-s USH_p pointer static;
>         dcl-ds ERRC0100 likeds(ERRC0100_t) INZ;
>         dcl-ds US likeds(UsrSpc_t) inz(*likeds);
>         dcl-s RtnLib char(10);
>         dcl-ds ZL likeds(ZLSL0100_t) based(ZL_p);
>         dcl-s ZL_p pointer static;
>         dcl-s idx1 uns(10);
>
>         dcl-pi *n;
>           iShare char(12);
>           iPath char(1000);
>           n_Share int(5);
>           n_Path int(5);
>           SQLSTT char(5);
>           Function varchar(517) const;
>           Specific varchar(128) const;
>           errorMsg varchar(70);
>           CallType int(10) const;
>         end-pi;
>
>           if CallType=call_open;
>             // Create user space
> 		.......
>             // Call list server info API
> 		.......
>             // Assign header pointer to user space
>             callp QUSPTRUS(US
>                 :USH_p);
>
>             ZL_p=USH_p+USH.QUSOLD;
>           elseif CallType=call_fetch;
>             // Assign pointer to API data
>             idx1+=1;
>             // Return EOF if end of list
>             if idx1>=USH.QUSNBRLE;
>               SQLSTT='02000';
>               return;
>             else;
>               iPath=ZL.PathName;
>               iShare=ZL.ShareName;
>               ZL_p+=USH.QUSSEE;
>             endif;
>           elseif CallType=call_close;
>             callp QUSDLTUS(US
>                 : errc0100);
>             clear USH;
>             clear ZL;
>             dealloc USH_p;
>             dealloc ZL_p;
>             clear idx1;
>             clear US;
>             *INLR=*on;
>
>           endif;
>         return;
>         end-proc;
> ___________________________________
> Darren Strong
> Dekko