| T.R | Title | User | Personal
Name | Date | Lines |
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| 3451.1 | Question entered in OZROCK::X25_OSF note 883 | HYDRA::NEWMAN | Chuck Newman, 508/467-5499 (DTN 297), MRO1-3/F26 | Tue Apr 08 1997 11:01 | 24 |
| <<< OZROCK::DISK$NAC$PUBLIC:[NOTES$LIBRARY]X25_OSF.NOTE;1 >>>
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Note 883.0 blocking in X25WaitForEvent when signal comes -- what happens? No replies
HYDRA::NEWMAN "Chuck Newman, 508/467-5499 (DTN 297), MRO1-3/F26" 18 lines 9-APR-1997 00:02
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A software developer contacted me with the following question. Would
someone please give me a definitive answer on this? Thanks!
-- Chuck Newman
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I am currently designing an application to accept X25 SVC connections
and plan to use the X25 for Digital UNIX Systems library (Product No.
AA-PR2KF-TE).
I wish to use the X25WaitForEvent function to block until an incoming
connection request is received. However In order to prevent the function
from blocking indefinately (if no calls arrive) I propose to send a
signal to the application whenever other processing is required. Am I
correct in assuming that this function will return with an error code of
X25RC_SYSERR and errno set to EINTR if I send a signal to this
application while it is blocking in the X25WaitForEvent function? This
should be mode effivient that constantly polling BUT the documentation
is a bit vague. Can you clarify this issue?
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| 3451.2 | Closing note sent to developer | HYDRA::NEWMAN | Chuck Newman, 508/467-5499 (DTN 297), MRO1-3/F26 | Tue Apr 08 1997 15:09 | 23 |
| From: AXPDEVELOPER "[email protected]"
To: [email protected]
Subject: Problem 1997-3451
Brian --
I posed your question to X25 engineering and they provided the following
response. If you still have questions with this issue, please reference
call number 1997-3451 and my name. Thanks.
-- Chuck Newman
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With V3.0 of our product, we are supporting the 'select' system call. This
is the more natural way of handling this requirement. In truth, your
programmer can use select() in earlier version as well.
Personally, I would urge your programmer to use the select() system call for
this operation, but if they do want to use X25WaitForEvent, then I would
expect that if the call is interrupted whilst it is blocked, then it would
return X25RC_SYSERR with errno set to EINTR.
Alternately, they could use a timeout in the call. Then you don't need to
worry about sending signals.
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| 3451.3 | response from vendor | HYDRA::NEWMAN | Chuck Newman, 508/467-5499 (DTN 297), MRO1-3/F26 | Wed Apr 09 1997 10:01 | 19 |
| Hello Chuck
Thank you very much for taking the time and trouble to respond to my
question so quickly.
Your X25 engineering group are correct in saying that using the select
function is the most natural way to handle incoming calls. We had
avoided this approach as the documentation gives several examples,
none of which use select. Previous experience prompted us to beleive
that the X25 port descriptors would not produce signals when they were
ready for IO as was the case when we used DECNet software.
I shall definately try and use the select function as it will simplify
the system enormously. Thanks you onces again for your swift response
it was greatly appreciated.
Regards
Brian Charlton - Principal Engineer VEGA Group PLC
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