Oh! I forgot to mention that in my logging process I do an FCONTROL 2 and
FCONTROL 6 to write the record and then update the EOF. That might explain
Stan's results.
Jack
-----Original Message-----
From: Stan Sieler [mailto:[log in to unmask]]
Sent: Thursday, September 21, 2000 2:11 PM
To: [log in to unmask]
Subject: Re: circular files-build, read, write to
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
|
