| Title: | Proudly built by the engineers of NaC Australia |
| Moderator: | DELNI::MUGGERIDGE |
| Created: | Mon Oct 12 1992 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 908 |
| Total number of notes: | 3829 |
A software developer contacted me with the following question. Would someone please give me a definitive answer on this? Thanks! -- Chuck Newman -------------------------------------------------------------------------------- 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?
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 883.1 | DELNI::MUGGERIDGE | Wed Apr 09 1997 03:32 | 13 | ||
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. Matt. | |||||
| 883.2 | Response from the software vendor -- thanks for the help | HYDRA::NEWMAN | Chuck Newman, 508/467-5499 (DTN 297), MRO1-3/F26 | Thu Apr 10 1997 00:03 | 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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