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From: wolff@inf.fu-berlin.de (Thomas Wolff)
Subject: Re: long group name bug / unique tid question
Message-ID: <6C2NBAKJ@math.fu-berlin.de>
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References: <Y0ZNB6CV@math.fu-berlin.de> <2p44hnINNgdq@duncan.cs.utk.edu>
Date: Thu, 21 Apr 1994 16:52:34 GMT
Lines: 32

papadopo@cs.utk.edu (Philip Papadopoulos) writes:

: In article <Y0ZNB6CV@math.fu-berlin.de> wolff@inf.fu-berlin.de (Thomas Wolff) writes:
: >1. Bug report and warning:
: >   The length of group names by which groups can uniquely be identified 
: >   is apparently restricted. I assigned long group names (ca. 60 characters) 
: >   and such a group was not recognized from another machine. There was no 
: >   error message and there is no apparent documentation on a length limit.
: You are right in that there is no documented limit but it is currently
: set at 32 characters ( I believe that Unix has the same limit on file
: names). However, you should have had pvm_joingroup return an error
: code because the name was beyond this limit. Did you check the return from
: pvm_joingroup?  
Yes, I did. If your question should mean that supplying a long group name 
to pvm_joingroup would already raise an error - it doesn't.
The actual routine failing was pvm_gettid which reported that no task 
with the given (long) group name would exist although it did exist.

: >   (Will this be corrected in the next release?)
: The 32 character limit will probably not be changed.  Documenting limit
: should be done, though.
Please do change it, and significantly. In the times of Gigabyte software 
there should not be data restrictions to extremely tiny values. The 
purpose was to generate unique group names for certain tasks to identify 
them even across multiple runs of the same program without recurring to 
the (system-supplied) task ids. So I took a (user supplied) task name and 
appended the local machine "hostid" and the exact current time to it - 
which already gets pretty long.

Is there a place in the sources where I could modify the limit myself?

Thomas Wolff@inf.fu-berlin.de

