OK. Now, suppose the initial module does a LOAD/LINK/XCTL/ATTACH after it totally loaded, but also after the parent task does a CLOSE on the DCB. What happens? I guess I could just run a job to find out.
On Fri, 2011-07-22 at 16:18 -0400, Jim Mulder wrote: > IBM Mainframe Discussion List <IBM-MAIN@bama.ua.edu> wrote on 07/22/2011 > 03:38:55 PM: > > > What about a driver program which OPENs a DD name then ATTACHes the > > actual "main" routine with the DCB=. This driver has an API such > > that a subtask can request the driver program, in its TCB, do a > > CLOSE / DEALLOCATE / ALLOCATE / OPEN of the DCB which it used in the > > ATTACH? Granted, this is likely very dangerous due to timing issues > > (or ENQ SMC). But does the IBM documentation explicitly say that the > > parent TCB cannot do this? "That which is not specifically > > forbidden, is allowed." > > > > <quote> > > ,DCB=dcb addr > > Specifies the address of the data control block for the > > partitioned data set containing the entry name. > > > > Note: The DCB must be opened before the ATTACH macro is issued > > and must be the DCB used in the BLDL that built the 62-byte DE list > > entry. The DCB must remain open until the subtask becomes active, > > and it should not be closed immediately following the ATTACH. > > > > Note: DCB must reside in 24-bit addressable storage. > > </quote> > > > > seems vague to me. Is the DCB actually used? Or the DEB pointed to > > by the DCB? The above says "should not be closed immediately". How > > long after the ATTACH? Or should it say only after the subtask > terminates? > > The DCB is used for fetching the module which is the target > of the ATTACH. This fetching is done under the newly created > task. So "how long" would be "not until the fetching of the > module has completed". If the module is fetched from a PDS, > then you would know that the fetching has completed when the > module gets initially entered. If the module is fetch from a PDSE, > and has the attributes with allow page-mode loading, then you don't > have a way to know when fetching as completed, so you should close > the DCB only after the subtask terminates. > > Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html -- John McKown Maranatha! <>< ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
