References to concatenated data sets

If you make a backward reference to a concatenation (using *.), the system obtains information only from the first data set defined in the sequence of DD statements.

If you make a forward reference to a concatenation (using the DDNAME parameter), the forward reference resolves to the first data set in the concatenation. If there are no DD statements between the forward reference and the concatenation, the rest of the data sets in the concatenation are appended to the first data set in the concatenation. The following example illustrates this.

 //STEP1      EXEC PGM=IEBGENER
 //SYSPRINT   DD   SYSOUT=*
 //SYSUT1     DD   DDNAME=INPUT
 //INPUT      DD   DSN=TSTDATA1,DISP=SHR
 //           DD   DSN=TSTDATA2,DISP=SHR
 //SYSUT2     DD   SYSOUT=*
 //SYSIN      DD   DUMMY

In this example, SYSUT1 will resolve to the first data set, TSTDATA1, defined by the DDNAME forward reference INPUT. TSTDATA2, the second data set in the DDNAME forward reference INPUT, will be appended to SYSUT1 as well. IEBGENER will recognize TSTDATA1 and TSTDATA2 as input.

If there are any DD statements between the forward reference and the concatenation, the rest of the data sets in the concatenation are appended to the last DD statement preceding the concatenation. For example:

 //STEP1      EXEC PGM=IEBGENER
 //SYSUT1     DD   DDNAME=INPUT
 //SYSPRINT   DD   SYSOUT=*
 //SYSUT2     DD   SYSOUT=*
 //INPUT      DD   DSN=TSTDATA1,DISP=SHR
 //           DD   DSN=TSTDATA2,DISP=SHR
 //SYSIN      DD   DUMMY

In the preceding example, SYSUT1 will resolve to the first data set, TSTDATA1, defined in the DDNAME forward reference INPUT. TSTDATA2 will be appended to SYSUT2, the last DD statement preceding the concatenation. In this example, IEBGENER will recognize only TSTDATA1 as input.

If a concatenated DD is added to a procedure, the remaining concatenated data sets will be concatenated to the last DD in the step named in an override or addition (or to the first step if no step was named in an override or addition). Note that this may result in these concatenated DDs being added to an unexpected DD. The following example illustrates this.

 //TPROC    PROC
 //S1         EXEC PGM=IEFBR14
 //DD1        DD   DDNAME=INPUT
 //DD2        DD   DSN=MYDSN2,DISP=SHR
 //DD3        DD   DSN=MYDSN3,DISP=SHR
 //S2         EXEC PGM=IEFBR14
 //DDA        DD   DDNAME=INPUT
 //DDB        DD   DSN=MINE2,DISP=SHR
 //DDC        DD   DSN=MINE3,DISP=SHR
 //           PEND
 //STEP1      EXEC TPROC
 //INPUT      DD   DSN=MYDSN1,DISP=SHR
 //           DD   DSN=MYDSN4,DISP=SHR
 //S2.INPUT   DD   DSN=MINE1,DISP=SHR
 //           DD   DSN=MINE4,DISP=SHR

In this example, the result of the DDNAME forward reference INPUT is:

In step S1, DD1 resolves to data set MYDSN1 and data set MYDSN4 is concatenated to data set MYDSN3.
In step S2, DDA resolves to data set MINE1 and data set MINE4 is concatenated to data set MINE3.