Re:

> One problem is that circular files can't be read while they are open for
> writing - but I got a tip off of this list several years ago - from Stan I
> believe, that allows you to copy the circular file to a flat file that you
> can then look at while the circular file is still open by another process.
>
>  FILE XXEACX=MSGPRINT.HISTORY;ACC=APPEND;SHR
>  COPY *XXEACX,XXEAC2
>  PURGE XXEAC2 > $NULL
>  COPY *XXEACX,XXEAC2
>
> The first copy command fails, but the second one works.

I hope it wasn't me:

  1) I don't recall that solution

  2) and it doesn't seem to work reliably.

I do remember noting the "can't be read while open" limitation, however.

I just tried a test on MPE/iX 6.0.

   :listf c,2
   ACCOUNT=  SIELER      GROUP=  SOURCE

   FILENAME  CODE  ------------LOGICAL RECORD-----------  ----SPACE----
                     SIZE  TYP        EOF      LIMIT R/B  SECTORS #X MX

   C       *          80B  FAO         16       1024  16      256  1  8

C is a CIRcular file, and is open (for SHR;APPEND) by a process on
terminal B.

BTW, that process has written only 4 records to the file, not 16.
OTOH, note that hte blockfactor is 16.

On terminal A, I do:

   :print c
          ^
   EXCLUSIVE VIOLATION: FILE ACCESSED EXCLUSIVELY  (FSERR 91)
   The PRINT command failed. (CIERR 9080)

So, I try explicitly sharing:
   :file c;shr
   :print *c
          ^
   EXCLUSIVE VIOLATION: FILE ACCESSED EXCLUSIVELY  (FSERR 91)
   The PRINT command failed. (CIERR 9080)

Then, I try a variation of Jack's approach:
  :file c;acc=append;shr
  :print *c



...(about 24 blank lines)


   (24/4) Continue? no
   :

Interesting, eh?
But not useful...so let's try "COPY" instead of "PRINT":

   :copy *c, d
   :listf d,2
   ACCOUNT=  SIELER      GROUP=  SOURCE

   FILENAME  CODE  ------------LOGICAL RECORD-----------  ----SPACE----
                     SIZE  TYP        EOF      LIMIT R/B  SECTORS #X MX

   D                  80B  FAO          4       1024  16      256  1  8

So...success?  Well...let's look closer:

   :print d
   LINE 1
   LINE 2


   :
I.e., two correct lines, and two blank lines.  (As you'll see below,
all four lines should have been non-blank!)

Now, terminate the process on terminal B, closing the file C.
And...
   :print c
   LINE 1
   LINE 2
   LINE 3
   LINE 4
   :

I.e.: there's no need to do a second "copy", AFAIK.

But...the copy wasn't accurate.

And...I just went back to try it again, and now I get:

   :copy *c, d
         ^
   COPY command cannot open the source file. (CIERR 9135)

So...I give up!

Stan Sieler                                           [log in to unmask]
www.allegro.com/sieler/wanted/index.html          www.allegro.com/sieler