Hi,
The documentation states that enumeration through a collection is
inherently NOT thread-safe, since a thread which added/removed an item from
said collection could screw up the thread that was iterating. That makes
sense.. but... given a collection that is filled at start-time and never
modified again, is it safe to have multiple threads *reading* (not writing
to) the collection using foreach()?
I have a class that exposes an event [which is really just a collection
of delegates]. The event registrants are all hooked up at startup. Is it
safe for my class to fire the event simultaneously from two different
threads even though this would lead to the delegate collection being
iterated by two different threads?
3  7968 
The following is taken from the SDK:
"An enumerator remains valid as long as the collection remains unchanged."
I don't see why any there would be any problem having multiple enumerators
in different threads on the same collection while nothing is modifying the
collection.
Ryan Byington [MS]
This posting is provided "AS IS" with no warranties, and confers no
rights.Use of included script samples are subject to the terms specified at http://www.microsoft.com/info/cpyright.htm
-------------------- From: "Grandma Wilkerson" <tu**@bottlenec k.scalability.c rash.dum>
Subject: Thread-safe enumeration thru collection?
Date: Thu, 17 Jul 2003 13:30:25 -0700
Lines: 19
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2800.1158
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165
Message-ID: <us************ **@tk2msftngp13 .phx.gbl>
Newsgroups:
microsoft.publi c.dotnet.genera l,microsoft.pub lic.dotnet.lang uages.csharpNNTP-Posting-Host: rrcs-west-66-27-51-213.biz.rr.com 66.27.51.213
Path: cpmsftngxa06.ph x.gbl!TK2MSFTNG P08.phx.gbl!tk2 msftngp13.phx.g bl
Xref: cpmsftngxa06.ph x.gbl microsoft.publi c.dotnet.langua ges.csharp:1699 90
microsoft.publi c.dotnet.genera l:101593X-Tomcat-NG: microsoft.publi c.dotnet.langua ges.csharp
Hi,
The documentation states that enumeration through a collection is
inherently NOT thread-safe, since a thread which added/removed an item from
said collection could screw up the thread that was iterating. That makes
sense.. but... given a collection that is filled at start-time and never
modified again, is it safe to have multiple threads *reading* (not writing
to) the collection using foreach()?
I have a class that exposes an event [which is really just a collection
of delegates]. The event registrants are all hooked up at startup. Is it
safe for my class to fire the event simultaneously from two different
threads even though this would lead to the delegate collection being
iterated by two different threads?
just lock() the critical sections on SyncRoot and you don't need to worry
"Ryan Byington" <ry*****@online .microsoft.com> wrote in message
news:tk******** ******@cpmsftng xa06.phx.gbl... The following is taken from the SDK:
"An enumerator remains valid as long as the collection remains unchanged."
I don't see why any there would be any problem having multiple enumerators
in different threads on the same collection while nothing is modifying the
collection.
Ryan Byington [MS]
This posting is provided "AS IS" with no warranties, and confers no
rights.Use of included script samples are subject to the terms specified
at http://www.microsoft.com/info/cpyright.htm
--------------------From: "Grandma Wilkerson" <tu**@bottlenec k.scalability.c rash.dum>
Subject: Thread-safe enumeration thru collection?
Date: Thu, 17 Jul 2003 13:30:25 -0700
Lines: 19
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2800.1158
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165
Message-ID: <us************ **@tk2msftngp13 .phx.gbl>
Newsgroups: microsoft.publi c.dotnet.genera l,microsoft.pub lic.dotnet.lang uages.csharpNNTP-Posting-Host: rrcs-west-66-27-51-213.biz.rr.com 66.27.51.213
Path: cpmsftngxa06.ph x.gbl!TK2MSFTNG P08.phx.gbl!tk2 msftngp13.phx.g bl
Xref: cpmsftngxa06.ph x.gbl
microsoft.publi c.dotnet.langua ges.csharp:1699 90 microsoft.publi c.dotnet.genera l:101593X-Tomcat-NG: microsoft.publi c.dotnet.langua ges.csharp
Hi,
The documentation states that enumeration through a collection is
inherently NOT thread-safe, since a thread which added/removed an item
fromsaid collection could screw up the thread that was iterating. That makes
sense.. but... given a collection that is filled at start-time and never
modified again, is it safe to have multiple threads *reading* (not
writingto) the collection using foreach()?
I have a class that exposes an event [which is really just a
collectionof delegates]. The event registrants are all hooked up at startup. Is it
safe for my class to fire the event simultaneously from two different
threads even though this would lead to the delegate collection being
iterated by two different threads?
Having every reader lock on the collection is inefficient.
What you might consider is a ReaderWriterLoc k. This allows
multiple readers and a single writer.
When a writer wants to write, it blocks until all the
readers are done (new readers are blocked) and then the
writer gets its turn. When the writer is done, then the
readers may resume.
-c
"mia lanui" <mi**@email.com > wrote in message
news:op******** *********@nwrdn y02.gnilink.net ... just lock() the critical sections on SyncRoot and you don't need to
worry
"Ryan Byington" <ry*****@online .microsoft.com> wrote in message
news:tk******** ******@cpmsftng xa06.phx.gbl... The following is taken from the SDK:
"An enumerator remains valid as long as the collection remains
unchanged."
I don't see why any there would be any problem having multiple
enumerators in different threads on the same collection while nothing is
modifying the collection.
Ryan Byington [MS]
This posting is provided "AS IS" with no warranties, and confers no
rights.Use of included script samples are subject to the terms
specified at http://www.microsoft.com/info/cpyright.htm
--------------------From: "Grandma Wilkerson" <tu**@bottlenec k.scalability.c rash.dum>
Subject: Thread-safe enumeration thru collection?
Date: Thu, 17 Jul 2003 13:30:25 -0700
Lines: 19
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2800.1158
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165
Message-ID: <us************ **@tk2msftngp13 .phx.gbl>
Newsgroups:
microsoft.publi c.dotnet.genera l,microsoft.pub lic.dotnet.lang uages.csharpNNTP-Posting-Host: rrcs-west-66-27-51-213.biz.rr.com 66.27.51.213
Path:
cpmsftngxa06.ph x.gbl!TK2MSFTNG P08.phx.gbl!tk2 msftngp13.phx.g blXref: cpmsftngxa06.ph x.gbl microsoft.publi c.dotnet.langua ges.csharp:1699 90 microsoft.publi c.dotnet.genera l:101593X-Tomcat-NG: microsoft.publi c.dotnet.langua ges.csharp
Hi,
The documentation states that enumeration through a collection
isinherently NOT thread-safe, since a thread which added/removed an
item fromsaid collection could screw up the thread that was iterating. That
makessense.. but... given a collection that is filled at start-time and
nevermodified again, is it safe to have multiple threads *reading* (not
writingto) the collection using foreach()?
I have a class that exposes an event [which is really just a collectionof delegates]. The event registrants are all hooked up at startup.
Is itsafe for my class to fire the event simultaneously from two
differentthreads even though this would lead to the delegate collection
beingiterated by two different threads?
This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
by: adeger |
last post by:
Having trouble with my first forays into threads. Basically, the
threads don't seem to be working in parallel (or you might say are
blocking). I've boiled my problems to the following short code block
and ensuing output. Seems like the output should be all interleaved
and of course it's not. Running Python 2.2 from ActiveState on
Windows XP (also doesn't work on Windows 2000).
Thanks in advance!
adeger
|
by: Gilles Leblanc |
last post by:
Hi I have started a small project with PyOpenGL. I am wondering what
are the options for a GUI. So far I checked PyUI but it has some
problems with 3d rendering outside the Windows platform.
I know of WxPython but I don't know if I can create a WxPython window,
use gl rendering code in it and then put widgets on top of that...
|
by: Ivan |
last post by:
Hi
I have following problem: I'm creating two threads who are performing some
tasks. When one thread finished I would like to restart her again (e.g. new
job). Following example demonstrates that. Problem is that when program is
started many threads are created (see output section), when only two should
be running at any time. Can you please help me to identify me where the
problem is?
Best regards
|
by: Matthew Groch |
last post by:
Hi all,
I've got a server that handles a relatively high number of concurrent
transactions (on the magnitude of 1000's per second). Client
applications establish socket connections with the server. Data is
sent and received over these connections using the asynchronous model.
The server is currently in beta testing. Sporadically over the course
of the day, I'll observe the thread count on the process (via perfmon)
start climbing....
|
by: droopytoon |
last post by:
Hi,
I start a new thread (previous one was "thread timing") because I have
isolated my problem.
It has nothing to do with calling unmanaged C++ code (I removed it in a
test application).
I have a thread "_itTaskThread" running.
The application is listening on a TCP port.
It accepts 2 connection from a client.
I simulate a crash on the client side (using "Debug->StopDebugging").
| | |
by: mareal |
last post by:
I have noticed how the thread I created just stops running. I have added
several exceptions to the thread
System.Threading.SynchronizationLockException
System.Threading.ThreadAbortException
System.Threading.ThreadInterruptedException
System.Threading.ThreadStateException
to see if I could get more information about why the thread stops running
but that code is never executed. Any ideas on how I can debug this?
|
by: Bob Day |
last post by:
Using vs2003, vb.net
I start a thread, giving it a name before start. Code snippet:
'give each thread a unique name (for later identification)
Trunk_Thread.Name = "Trunk_0_Thread"
' allow only 1 thread per line
Trunk_Thread.ApartmentState = ApartmentState.STA
|
by: Charles Law |
last post by:
My first thought was to call
WorkerThread.Suspend
but the help cautions against this (for good reason) because the caller has
no control over where the thread actually stops, and it might have a lock
pending, for example.
I want to be able to stop a thread temporarily, and then optionally resume
it or stop it for good.
|
by: jayesah |
last post by:
Hi All,
I am writting a Thread class with using pthread library. I have some
problem in saving thread function type and argument type. How to make
Thread class generic ?
/* This is my global Function */
template < class FunType, class ArgType>
Thread makeThread(Funtype fun, ArgType arg)
|
by: John Nagle |
last post by:
There's no way to set thread priorities within Python, is there?
We have some threads that go compute-bound, and would like to
reduce their priority slightly so the other operations, like
accessing the database and servicing queries, aren't slowed
as much.
John Nagle
|
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it.
Here is my compilation command:
g++-12 -std=c++20 -Wnarrowing bit_field.cpp
Here is the code in...
| | |
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
The Art of Business Website Design
Your website is...
|
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules.
He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms.
Adolph will...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert into image.
Globals.ThisAddIn.Application.ActiveDocument.Select();...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
|
by: 6302768590 |
last post by:
Hai team
i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
| | |
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
|
by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...
| |
