I must ask this: USS = Posix compliance which = No Enqueues... so
how else can Unix keep Bill from stepping on Bob's data sets if
the flags = JackPot!! (777).
On 9/17/2025 12:12 PM, Paul Gilmartin wrote:
On Tue, 16 Sep 2025 11:24:38 -0500, Charles Mills wrote:
Follow-up question if I may:
Would you expect (your command(s) here) | cp - "//DD:MYDDNAME" to work if the
command were executed from Rexx using SYSCALLS and BPXWUNIX?
or ADDRESS SYSCALL spawn.
(Assuming all of the usual -- good allocation, RACF authorization, no ENQ
conflicts, etc.)
Some programmers rely on _BPX_SHAREAS=MUST for this.
I believe redirection needs a descriptor.
open() returns a descriptor but doesn't handle Classic data sets.
fopen() handle s Classic data sets but doesn't return a descriptor.
After fopen(), fileno() returns the file descriptor for the FILE.
<https://www.ibm.com/docs/en/zos/3.1.0?topic=functions-fileno-get-file-descriptor-from-open-stream>
MVS data sets are not supported, so fileno() of an MVS data set returns -1.
Some operations on UNIX files are nearly impossible on MVS data sets.
I am asking because the doc says
In order to use the //DD:DDNAME format, the dataset must be allocated in the
address space that the following command will run in. However, in the login
shell environment, the user cannot use the //DD:DDNAME format due to the
restriction that the address space of the allocated dataset is not always the
same as the running command.
I read that as "it might work, and it might not -- and even if it worked in test, it
might not work in production."
--
Regards,
Steve Thompson
Make Mainframes Great Again
They use far less Electricity than Clouds and can do more work
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