by sancelo » Wed, 12 Jan 2000 04:00:00
I tried sem_open for use of named sempahores, but it did not worked ,
errno = Function not implemented .
What is the best way to communicate via events between processes at this
time, on linux
thanks for help
steph
by Kaz Kylhe » Wed, 12 Jan 2000 04:00:00
>I tried sem_open for use of named sempahores, but it did not worked ,
>errno = Function not implemented .
Traditional mechanisms such as pipes, sockets, System V IPC.Quote:>What is the best way to communicate via events between processes at this
>time, on linux
by Damir Cosi » Wed, 12 Jan 2000 04:00:00
> I tried sem_open for use of named sempahores, but it did not worked ,
> errno = Function not implemented .
> What is the best way to communicate via events between processes at this
> time, on linux
> thanks for help
> steph
Damir Cosic
by fernand » Thu, 13 Jan 2000 04:00:00
> I would be aple to share semaphore between processes.
> I tried sem_open for use of named sempahores, but it did not worked ,
> errno = Function not implemented .
> What is the best way to communicate via events between processes at this
> time, on linux
> thanks for help
> steph
1. semaphore questions, two different ones
I'm trying to use semaphores for the first time, mainly using Stevens (Adv.
Prog. in Unix Env) as reference. I initially thought it was pretty
straight-forward, but I'm having some problems that I don't understand...
1. I created a semaphore successfully, but in my shutdown routine I want to
release to release the semaphore. I initially was trying to use semop(...
IPC_RMID), but this fails with "invalid argument". Based on an example
elsewhere on the web, I instead used semctl(... IPC_RMID)... this succeeded,
but I noticed that on subsequent semaphore acquisitions (when I reload my
daemon), the semaphore number is jumping by about 120 per load. I expected
it to increase by one at each instance, didn't I?? Why is this happening??
And what do I have to put in the sembuf struct if I want to use semop() for
this purpose??
2. In any case, what I'm trying to do with the semaphore is prevent
simultaneous access to a data struct in my daemon, if it's accessed several
times in close succession (which it is...). In a device driver, I'd just
use cli()/sti() to access a mutex flag, but I can't do that in a daemon; are
semaphores the appropriate method for doing this, or is there some better
way??
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