Mark Baranowski (baranowski++at++marklynn.demon.co.uk)
Fri, 04 Jul 1997 08:16:49 GMT
>Hello all:
>
>I have a process that sets up a pfDataPool. I wrote another ViewKit based
>program that attaches to the pfDataPool. That works fine. When I try to
>attach to the same pfDataPool with my Performer program I get errors and
>cannot attach.
>What can I do to attach to this pfDataPool? Below are errors.
>Thank you,
As pfDataPools are based on shared arenas this sounds like the problem
of the default attach address (when the arena (datapool) is created)
not being outside the process address space of all the programs
wishing to attach to it.
If this is the problem, one solution would be to make sure the
datapool is created by your 'largest' process (i.e. make sure you run
your largest program first). Thus the attach address used would be
acceptable to all the programs wishing to attach. (Setting the
environment variable USTRACE before running will give you info on the
attach address selected for the arena when it is created).
Alternatively, do as the warning suggests and explicitly set an attach
address which is acceptable to all your programs. Then you can run
your programs in any order. Instead of hard coding the address, I
would suggest the use of an environment variable. If the variable does
not exist then you can resort to the default behaviour.
>PF Warning/SysErr(16) pfDataPool::attach() by pid 15377 could not map datapool
>/usr/tmp/pmSharedData.pfdpool.
>
>PF Required address already in use. Try attaching earlier in program or call
>pfDataPool::setAttachAddr() before pfDataPool::create().
>
>P.S. I had these same errors in my ViewKit program and so I did the attaching
>early on in "main" and it worked. Doing the same for my Performer program did
>not make any difference.
I am not sure however, why attaching earlier would make a difference
(other than affecting the outcome of the race condition which exists
when multiple processes are trying to create the arena/datapool). If
this isn't the case, can anybody else please explain?
Regards,
Mark.
--
Mark Baranowski at work (baranowski++at++marklynn.demon.co.uk)
Pera, VR Division. Melton Mowbray, Leics. LE13 0PB. UK.
Tel: +44 (0)1664 501501, Fax: +44 (0)1664 501553
All opinions expressed are my own and should not be viewed
as representing my employer unless stated otherwise.
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