Since RPG has built in support for data areas, we have found little need to use the API with RPG. However, PL/I has no support for data areas, so we wrote a function using the QWCRDTAA API to retrieve data areas for use in our PL/I programs. Perhaps you can gleen some information from this code. One important thing to remember about this API is that the data area's value is returned in the same field, regardless of the type and Packed fields are not converted to readable characters. I hope this helps. Sorry I don't have an RPG example for you

 RTVDTAARA:  PROCEDURE (DTAARA,LIB)  RETURNS(CHAR(1024) VARYING);



     DCL        DTAARA    CHAR(10);
     DCL        LIB       CHAR(10);

     Dcl        DecVal    Char(31) Varying;

   Dcl (Int,I) Bin(15);
   Dcl Char1 Char(1);


     %INCLUDE QPLIINCL(TRIM);
 Dcl 1 ErrRtn Static,
     5 ErrStrLen     Bin(31) Unaligned Init(272),
     5 ErrRtnLen     Bin(31) Unaligned,
     5 ErrMsgID      Char(7),
     5 Filler        Char(1),
     5 ErrMsgDta     Char(256);

   Dcl QWCRDTAA Ext Entry
                 (*,    /* Return variable           */
                  Bin(31),    /* Length of return variable */
                  Char(20),   /* Qualified data area name  */
                  Bin(31),    /* Start position            */
                  Bin(31),    /* Length to retrieve        */
                  *))                       /* Error code structure    */
                Options(Assembler);


   Dcl 1 Value_St,
         5 AvailBytes        Bin(31) Unaligned,
         5 RtnBytes          Bin(31) Unaligned,
         5 Type              Char(10),
         5 RtnLib            Char(10),
         5 RtnLen            Bin(31) Unaligned,
         5 DecPos            Bin(31) Unaligned,
         5 Value             Char(1024);

  ON ERROR  GOTO EOJ;


 IF (LIB=' ') THEN LIB = '*LIBL';
 Call     QWCRDTAA   (Value_St,1060,DTAARA³³LIB,-1,1024,ErrRtn);
 Select(Value_St.Type);
   When ('*LGL','*CHAR')
     Return(Substr(Value,1,RtnLen));
   When ('*DEC')
     Do;
       DecVal = '';
       Do i = 1 to RtnLen/2 + 1;
         Char1 = substr(value,i,1);
         /* moves the first four bits to an interger field */
         int = substr(unspec(char1),1,4);
        /* convert integer to character and append  */
        DecVal = DecVal||Trim(Char(int));
         /* moves the first four bits to an interger field */
          int = substr(unspec(char1),5,4);
         Select(int);
           When(0,1,2,3,4,5,6,7,8,9)
             DecVal = DecVal|| Trim(Char(int));
           When(13) /* x'D' found make value negative */
             DecVal = '-'|| DecVal;
           When(15); /* x'F' found value is positive, ignore it */
         End;
       End;
       If DecPos > 0 Then
         DecVal = Substr(DecVal,1,Length(DecVal)-DecPos) ||'.'||
                  Substr(DecVal,Length(DecVal)-DecPos+1);
       Return(DecVal);
     End;
 End; /* Select */
 EOJ: Return('NOT FOUND');
 END RTVDTAARA;

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Here is an example of using QWCRDTAA from ILE RPG.

  D* copy qsysinc/qrpglesrc,qwcrdtaa into source to change QWCVALUE
     DQWCRDRTN         DS
     D*                                             Qwc Rdtaa Data Return
     D QWCBAVL                 1      4B 0
     D*                                             Bytes Available
     D QWCBRTN                 5      8B 0
     D*                                             Bytes Returned
     D QWCTVRTN                9     18
     D*                                             Type Value Returned
     D QWCLIBN                19     28
     D*                                             Library Name
     D QWCLVRTN               29     32B 0
     D*                                             Length Value Returned
     D QWCNBRDP               33     36B 0
     D*                                             Number Decimal Positio
     D QWCVALUE               37    512
     D*
     D*                             Varying length MODIFIED and uncommente
     D*
     D/copy qsysinc/qrpglesrc,qusec
     D*
     Drcvvarsiz        s             10i 0 inz(512)
     Ddataname         s             20    inz('DTAARA    DTALIB    ')
     Dstrpos           s             10i 0 inz(-1)
     Dstrlen           s             10i 0 inz(475)
     C*
     C                   eval      QUSBPRV = 0
     C                   call      'QWCRDTAA'
     C                   parm                    QWCRDRTN
     C                   parm                    rcvvarsiz
     C                   parm                    dataname
     C                   parm                    strpos
     C                   parm                    strlen
     C                   parm                    QUSEC
     C* The variable QWCVALUE now contains the *DTAARA value
     C                   eval      *inlr = '1'
     C                   return

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Whenever you define a binary field in the D-specs in RPG IV, you need to make it 9 positions. The API docs make you assume 4 positions, but that is the physical length. Remeber, most of the API documentation was written before RPG 4 came out. Make sure that the receiver variable is as long as the longest data area you'll be accessing, and the length parameter must match it. Code your DS in RPG III with the binary values as B 4, run it through CVTRPGSRC, and you'll see what I mean. HTH,

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