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Can somebody please explain me what semaphores are? there purpose? and there effects?
Thanks in advance:) (0 Replies)
Discussion started by: Laxxi
Hi, I've used the following way to set ssh public key authentication and it is working fine on Solaris 10, RedHat Linux and SuSE Linux servers without any problem. But I got error 'Server refused our key' on Solaris 8 system. Solaris 8 uses SSH2 too. Why? Please help. Thanks.
... (1 Reply)
Discussion started by: aixlover
3. UNIX for Dummies Questions & Answers
I am having problem with semaphores. I am trying to protect line where process prints so that every process with print in proper order.This is the code..
union... (3 Replies)
Discussion started by: joker40
4. UNIX for Advanced & Expert Users
Hello, first of all I apologize if this thread is not in the correct section of this forum, but this one just seemed the most appropriate.
The question I have does not concern Unix specifically, it applies to virtually any OS, however it is in Unix where I learned about this problem.
So, the... (8 Replies)
Discussion started by: Watto86
been searching around on how to use an up and down function with semaphores but i can't find an example. i looked into using: "semop" but i have no idea how to use it. I have been able to declared the semaphores using semget and initializing them using semctl. (7 Replies)
Discussion started by: ddx08
6. Shell Programming and Scripting
If i execute this command it comes back with 300 lines:
ipcs|grep cerebrus >>> i would like to clear the semaphores but ipcrm can remove one id at a time. is there a quicker way of removing semaphores maybe using awk?
Regards, (1 Reply)
Discussion started by: kekanap
Could someone please confirm which POSIX semaphore routines should be used for a multiprocess (and not multithreaded) environment?
sys/sem.h definitely works. but the routines, semget, semctl, semop are pretty unwieldy. So, I am looking for an easier way out.
From the man pages... (2 Replies)
Discussion started by: qntmteleporter
8. UNIX for Dummies Questions & Answers
I am using HP 10.20 on A 9000/785. My question is:
If I am the only person logged in as root at the moment, how many "semaphore proccesses" should I have?? Is it only one, or it is relevant to other system proccesses?
Here is what I get listing the current semaphores
# ipcs -sp... (1 Reply)
Discussion started by: guest100
I'm in a multiprocess environment working with shared mem and semaphores as mutex.. The problem is -- If one of the process hooked up with the semaphore and accessing the shared mem, terminates abruptly ( or got killed ), other process which are in want of the semaphore are... (1 Reply)
Discussion started by: joseph_shibu
SEM_GET(3) 1 SEM_GET(3)
sem_get - Get a semaphore id
resource sem_get (int $key, [int $max_acquire = 1], [int $perm = 0666], [int $auto_release = 1])
sem_get(3) returns an id that can be used to access the System V semaphore with the given $key.
A second call to sem_get(3) for the same key will return a different semaphore identifier, but both identifiers access the same underlying
- The number of processes that can acquire the semaphore simultaneously is set to $max_acquire.
- The semaphore permissions. Actually this value is set only if the process finds it is the only process currently attached to the
- Specifies if the semaphore should be automatically released on request shutdown.
Returns a positive semaphore identifier on success, or FALSE on error.
|Version | |
| | |
| | Description |
| | |
| 4.3.0 | |
| | |
| | The $auto_release parameter was added. |
| | |
When using sem_get(3) to access a semaphore created outside PHP, note that the semaphore must have been created as a set of 3 sema-
phores (for example, by specifying 3 as the nsems parameter when calling the C semget() function), otherwise PHP will be unable to
access the semaphore.
sem_acquire(3), sem_release(3), ftok(3).
PHP Documentation Group SEM_GET(3)