Re: PCO's Name Resolution List and PCO's QTEMP position in *LIBL, on V5R1 and above

Gene Gaunt wrote:

> Try MATPRATR option x'18' then back up two bytes to get QTEMP position.
>
> dcl dd     data        auto char(32) bdry(16);
> dcl dd     datalength  def(data) pos(1) bin(4) init(32);
> dcl spcptr nrl@        def(data) pos(17);
> dcl sysptr libl@(250)  bas(nrl@) pos(17);
> dcl spcptr data@       auto init(data);
> dcl mspptr work@;
> dcl dd     qtemppos    bas(work@) pos(1) bin(2);
>
> matpratr   data@, *, X"18";
> subspp     work@, nrl@, 2;
> brk        "1";
> pend;


I'm assuming from your code that MATPRATR returns a pointer to the 16 bytes
preceding the actual NRL.  Shouldn't your library pointer list (libl@) be
268 to accommodate the total possible list?

The QTEMP position indicator is 18 bytes before the first library (pointer)
in the list.  The eight bytes before the first entry is a machine timestamp,
and the 2-byte QTEMP position indicator is 10 bytes before that.  The 2-byte
count of total libraries follows that.  The 2-byte count of system libraries
precedes the QTEMP position indicator. The H'0000010C' at offset 1DE0
appears to be the count of how many library pointers there can be (H'10C' is
268 - 15 system libraries, 2 product libraries, 1 current library, and 250
user libraries).  See the partial *PCS dump below (V5R3):

001DE0   0000010C 00000000 00000000 0009000A   000E0000 00000000 8DBC196B
F9250000
001E00   00008000 00000000 0A573286 C10004FF   00008000 00000000 3B6778EE
920004FF
001E20   00008000 00000000 3C652042 CB0004FF   00008000 00000000 298E90AF
F70004FF

In this library list there are 9 libraries in the system portion of the
list, the QTEMP position indicator is in the 10th position (the first
library in the user portion of the list) which you can see as 000A above,
and there are 14 total libraries (000E) in the list.  The timestamp
(8DBC196B F9250000) equates to 1-07/08/28-13:55:04.308.  The timestamp is
that last time the NRL was manipulated (via ADDLIBLE, RMVLIBLE, or
CHGSYSLIBL) since the NRL was initially set (the timestamp is initially all
H'00').  The first library pointer is at offset 1E00.

The data is structured the same way for all releases, and, in fact, was the
same on the System/38 (at least as of the last release, release 8).  The
only thing that has changed is where the NRL list starts within the PCO.  It
changed from offset 832 (H'340') on the System/38 to offset 1296 (H'510') on
V1R1 of OS/400, to offset 7552 (H'1D80') on V5R1, to offset 7680 (H'1E00')
on V5R2 and V5R3, and to offset 8608 (H'21A0') on V5R4.  Who knows where it
will be on V6R1?

I've been just adding code to detect the release and change the offset
accordingly, but I'm definitely going to use Gene's suggestion (thanks
Gene).

The real question is will we be able to get to this on V6R1?  Currently this
is in the associated space of the *PCS and is in the user domain.  Will this
change on V6R1?

_______________________________________________
This is the MI Programming on the AS400 / iSeries (MI400) mailing list
To post a message email: MI400-Zwy7GipZuJhWk0Htik3J/[email protected]
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/mi400
or email: MI400-request-Zwy7GipZuJhWk0Htik3J/[email protected]
Before posting, please take a moment to review the archives
at http://archive.midrange.com/mi400.