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Location in the JCL z/OS MVS JCL Reference SA23-1385-00 |
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Place a DD statement containing a DDNAME parameter in a job step or in a cataloged or in-stream procedure. The referenced DD statement must be later in the same job step, must be in the calling job step, or must be in a cataloged or in-stream procedure called by the job step. Do not use the name of a DDNAME statement more than once within the same step. Location of DD statements for concatenated data sets: To concatenate data sets to a data set defined with a DDNAME parameter, the unnamed DD statements must follow the DD statement that contains the DDNAME parameter, not the referenced DD statement that defines the data set. Errors in location of referenced DD statement: The system
treats a DDNAME parameter as though it were a DUMMY parameter and
issues a warning message in the following cases:
Location of DD statement requesting unit affinity: To use the same device, a DD statement
can request unit affinity to an earlier DD statement by specifying
UNIT=AFF=ddname. If a DD statement requests unit affinity to a DD
statement containing a DDNAME parameter, the DD statement requesting
unit affinity must be placed after the referenced DD statement. If
the DD statement requesting unit affinity appears before, the system
treats the DD statement requesting unit affinity as a DUMMY DD statement.
DD1 postpones defining the data set until DD4. DD5 requests unit affinity to DD1. Because DD1 has been defined when DD5 is processed, the system assigns DD5 to the same device as DD1. Instead of specifying UNIT=AFF=ddname, both DD statements can specify the same devices in their UNIT parameters or the same volume serials in their VOLUME parameters. |
Copyright IBM Corporation 1990, 2014
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