Semaphores problem

Tags

programming

Top Forums Programming Semaphores problem

11-10-2012

Registered User

2, 0

Join Date: Nov 2012

Last Activity: 11 November 2012, 5:29 PM EST

Posts: 2

Thanks Given: 0

Thanked 0 Times in 0 Posts

Semaphores problem

hallo!
if there are many processes running and I initialize the semaphore like this:

Code:

my_sem = sem_open(SEM_NAME, O_CREAT | O_RDWR, 
S_IRUSR | S_IWUSR, 10);
(the last argument is 10)


and then i use
sem_wait(my_sem);
sleep(5);
sem_post;

Will 10 processes be able to access the critical section on the same time and sleep or only one process can do that?
And if not how is it possible to make max 10 processes sleep at the same time?

Moderator's Comments:

Review Homework Rules. Thank You.

whatevernever

View Public Profile for whatevernever

Find all posts by whatevernever

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. Homework & Coursework Questions

Semaphores sem_wait sem_post problem

hallo! if there are many processes running and I initialize the semaphore like this: my_sem = sem_open(SEM_NAME, O_CREAT | O_RDWR, S_IRUSR | S_IWUSR, 10); (the last argument is 10) and then i use sem_wait(my_sem); sleep(5); sem_post; Will 10 processes be able to access the...

2. UNIX for Dummies Questions & Answers

semaphores

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.. #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/ipc.h> #include <sys/sem.h> #include <sys/types.h> union...

3. Programming

Problem with semaphores

Hello, I was doing an exercise of semaphores and shared memory, namely the barbers: -B number of barbers -S number of chairs -C number of customers. I have done already and I compiled the code, but when run I get an error segment. Can not be and it took several days. If anyone sees the error...

4. UNIX for Advanced & Expert Users

How many semaphores?

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...

5. Programming

semaphores using up and down

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.

6. Shell Programming and Scripting

semaphores

Hi Friends, 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,

7. Programming

semaphores

Hi there, 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...

8. UNIX for Dummies Questions & Answers

Semaphores

Hi all, 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...

9. Programming

Semaphores

Dear Reader, 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...

Programming