I was asked to add this piece of code to a c program which I will execute through the shell:
I didn't get it, which is the critical section ? if it's "count++" how would a thread wake up in order to enter it if the post comes after this critical section ?.
From my understanding post is the action that wakes up the thread in the queue, or increasing the semaphore by 1 if no threads are waiting.
I'm running one multithreaded application, in that one of my thread
is waiting infinitely in a semphore. Is there a way to determine, in
which semaphore the particular thread is waiting and which thread(s)
is holding the semaphore. (5 Replies)
Hi All,
I am going through the semaphore concept and have a doubt regarding the same and hope to get a resolution here.
I have a file which has a number of records.
I want to write an application (in C) which will be able to do concurrent read/write on these records.
Of what I have... (8 Replies)
Hi,
I am looking to use a semaphore for the first time in one of my scripts. I am just wondering if there are any simple examples or tutorials around?
I am a beginner so the simpler the better :)
Thanks
-Jaken (2 Replies)
In my server code there is a thread per client...
The server call accept() and after that start the thread.
So there is a thread for client that save in RAM the client's message, that will be send to other clients.
Now in RAM I have created a shared memory in which thread read and write(save)... (2 Replies)
Control two exclusively shared resources(semaphore). The two resources are two files. The producer will write even numbers to one file, and odd numbers to another one. The consumer respectively reads from each file until it gets 5 even numbers and 5 odd numbers.
Can any one help me with the... (0 Replies)
If I create a semaphore and then I fork a number of child processes then all the child process use that same semaphore.
Since the process address spaces are different rfom each other then how all the child process are able to access the same semaphore?
I understand that semaphore/mutex is at os... (0 Replies)
Can anyone tell me abt the Semaphore concept and what is semaphore???
is semaphore id is associated in terms as in resources like semaphore id 1 indicates cpu share unit is given and semaphore id 2 will indicate abt the memore or semaphore id 3 will tell us the i/o components (1 Reply)
Discussion started by: aarjun07
1 Replies
LEARN ABOUT DEBIAN
ns_masterlock
Ns_Master(3aolserver) AOLserver Library Procedures Ns_Master(3aolserver)__________________________________________________________________________________________________________________________________________________NAME
Ns_MasterLock, Ns_MasterUnlock - Enter and leave the single master critical section lock
SYNOPSIS
#include "ns.h"
void
Ns_MasterLock(void)
void
Ns_MasterUnlock(void)
_________________________________________________________________DESCRIPTION
The single master critical section lock is used throughout the core server to protect portions of code from being run by more than one
thread at a time. These are convenience functions which actually make calls to Ns_CsEnter and Ns_CsLeave to perform the locking and unlock-
ing function.
You should not use these functions in your modules. To protect critical sections in your modules you should create and initialize your own
named locks, then wrap your critical sections with calls to Ns_CsEnter and Ns_CsLeave.
Ns_MasterLock()
Enter the single master lock. The thread that holds this lock is guaranteed exclusive access to the section of code that follows the
call to Ns_MasterLock. Other threads that attempt to enter the master critical section while another thread owns the master lock
will block until the owning thread releases the master lock.
Be extremely careful with code you place within the master critical section. If the thread that owns the master lock blocks for any
reason while in the master critical section, other threads that need to enter that section of code will block until the master lock
is released.
Ns_MasterUnlock()
Leave the single master critical section. The thread that owns the lock must release it after the critical section of code has com-
pleted so that other threads may execute the critical section code.
SEE ALSO nsd(1), info(n), Ns_CsEnter(3), Ns_CsLeave(3)KEYWORDS AOLserver 4.0 Ns_Master(3aolserver)