On Sun, 9 May 2010 10:52:28 -0400, Shmuel Metz (Seymour J.) wrote:
>
>>How can there ever be an "empty generated SYSIN DD *"?
>
>The obvious way, if it works, is to place a /* statement after another
>JCL statement.
>
By experiment, it does not. It might be notionally more consistent
if it did.
>>The SYSIN DD * is generated only if there's a line in the JCL
>>causing it to be generated, hence it's nonempty.
>
>There is no hence as you worded it. If the line causing //SYSIN DD *
>to be generated is a /* line, then an empty data set is what you
>should get.
>>And I believe that it has been written here that DFSORT treats SYSIN
>>DD DUMMY differently from an empty non-DUMMY SYSIN.
>
>If true it were a grievous fault. That's worse than barfing on an
>empty SYSLIN.
>
I misstated; it was ICEGENER, not exactly DFSORT.
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URL: http://bama.ua.edu/cgi-bin/wa?A2=ind0801&L=ibm-main&P=R69541
From: Frank Yaeger <yae...@us.ibm.com>
Date: Tue, 15 Jan 2008 14:48:05 -0800
(Replying to John McKown)
Yes, DUMMY or NULLFILE or no SYSIN DD is required to have ICEGENER use
DFSORT copy.
ICEGENER does not consider an empty data set to be the same as DUMMY.
I suppose it could, but it doesn't and AFAIK you're the first person to
ever mention it as a concern. I don't think I'd want to change it at
this point because if I did, somebody else would surely complain that
it doesn't work the way it used to. :-)
>>Similarly, DUMMY in a concatenation behaves differently from an
>>empty non-DUMMY data set in the same concatenation.
>
>Do you mean only that it's different from an empty data set with the
>same attributes as the rest of the concatenation, or that it's
>different from an unlike attributes concatenation not involving DUMMY?
>If the latter, is there still a difference when the DCB has the
>"unlike attributes" bit set?
>
Linkname: 12.1.6.8 "z/OS V1R10.0 MVS JCL Reference"
URL:
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/iea2b680/12.1.6.8
12.1.6.8 Do Not Concatenate Data Sets after a DUMMY Data Set
If you define a data set using the DUMMY
parameter, do not concatenate other data sets after it. When the processing
program
asks to read a dummy data set, the system takes an end-of-data set exit
immediately and
ignores any data set that might be concatenated after the dummy.
... which is not the behavior of an empty non-DUMMY data set,
regardless of attributes.
-- gil
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