Truong Hong Thi on .NET

Thanks a lot. I was looking for this. This will he...

2009-09-16T19:55:45.295+07:00

Thanks a lot. I was looking for this. This will help me.

The World Leading wow power leveling and wow gold...

2009-07-15T09:45:20.795+07:00

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Thanks Truong for your reply.

2009-06-07T20:38:00.298+07:00

Thanks Truong for your reply.

Hi Jehanzeb, Because all accesses to isGateOpen a...

2009-06-07T15:08:13.361+07:00

Hi Jehanzeb,

Because all accesses to isGateOpen are already atomic, in order to make MyManualResetEvent thread-safe regardless of memory model, simply add "volatile" keyword to the declaration of MyManualResetEvent's isGateOpen.

private volatile Boolean isGateOpen;

The "volatile" keyword prevents optimizations such as reordering or caching, and it is optimal in this situation.

For the purpose of understanding the construct implementation, your second class, ThreadSafeManualResetEvent, is correct.
However, I suggest to change WaitOne like this:

public void WaitOne()
{
int gateState = 0;
while (Interlocked.Exchanged(ref gateState, this.isGateOpen) == 0)
Thread.Sleep(1000); // "Spin-Sleeping!"
}

Hi, I am trying to get better understanding of th...

2009-06-07T01:26:26.421+07:00

Hi,

I am trying to get better understanding of threading and synchronization constructs. So I decided to implement some on the synchronization constructs myself. Can you review my implementations and validate if they are correct?

Ignore the spin-wait logic, I know it's not optimal. As I said, the purpose if to understand the construct implementation.

public sealed class MyManualRestEvent
{
private Boolean isGateOpen;

public MyManualRestEvent(Boolean initialState)
{
this.isGateOpen = initialState;
}

public void ReSet()
{
//It's not thread-safe
this.isGateOpen = false;
}

public void Set()
{
//It's not thread-safe
this.isGateOpen = true;
}

public void WaitOne()
{
//It's not thread-safe
while (!this.isGateOpen) Thread.Sleep(1000); // "Spin-Sleeping!"
}
}

public sealed class ThreadSafeManualResetEvent
{
// It can possibly have only two false, 0 and 1.
// 0 - Gate is closed. Thread can not enter critical section.
// 1.- Gate is open. Waiting threads can enter the critical section.
private Int32 isGateOpen;

public ThreadSafeManualResetEvent(Boolean initialState)
{
Interlocked.Exchange(ref this.isGateOpen, initialState ? 1 : 0);
}

public void ReSet()
{
Interlocked.Exchange(ref this.isGateOpen, 0);
}

public void Set()
{
Interlocked.Exchange(ref this.isGateOpen, 1);
}

public void WaitOne()
{
while (Interlocked.CompareExchange(ref this.isGateOpen, this.isGateOpen, this.isGateOpen) == 0)
Thread.Sleep(1000); // "Spin-Sleeping!"
}
}

Regards,
Jehanzeb

thanks. very helpful.

2009-05-26T14:35:56.555+07:00

thanks. very helpful.

I have a simple solution for VB6 code. See http://...

2008-10-21T04:20:00.000+07:00

I have a simple solution for VB6 code. See http://obviouslysomething.blogspot.com/2008/10/formatting-visual-basic-6-code-for-html.html.

For other languages, http://puzzleware.net/codehtmler/default.aspx is very good.

How about using a delegate to create the Singleton...

2008-10-09T00:50:00.000+07:00

How about using a delegate to create the Singleton instance? you could have the delegate executed only if the singleton reference is null, to ensure it is only instantiated once.

Repairing your registry on your own is very tricky...

2008-06-03T20:14:00.000+07:00

Repairing your registry on your own is very tricky. Even the most advanced users usually stay away from it, since one bad move can do serious harm.

The other alternative is to use a registry cleaner. You can get a review of the top programs here: www.registryrepaironline.com

Arguments to method invocations are always evaluat...

2008-02-22T17:22:00.000+07:00

Arguments to method invocations are always evaluated before the method is invoked. So the new singleton will always be created. Late-bound evaluation of arguments is a whole topic in itself.

We're also discussing this subject over at http://www.janus-net.de/2008/01/10/double-checked-locking-in-c/.

I think "no operation is performed" means value is...

2007-12-16T15:12:00.000+07:00

I think "no operation is performed" means value is not stored in the destination. A new instance is always created to pass to the CompareExchange Method, no matter what CompareExchange does.

Can you please make your code publicly available?

2007-09-18T11:14:00.000+07:00

Can you please make your code publicly available?

Wonderful. Thanks for posting. Now I can now blog ...

2007-09-14T14:10:00.000+07:00

Wonderful. Thanks for posting. Now I can now blog snippets without them hiding in black hole of unseen content.

Just to try and make it clearer I edited the html in my eBlogger template and addded the csharp.css contents with the modification mentioned after the last template CSS.

Be sure to save a backup of your complete template html, because clicking on another template will reset your modifications!

Related to last sentence (using Interlocked.Compar...

2007-07-04T22:23:00.000+07:00

Related to last sentence (using Interlocked.CompareExchange Method): I think that new SingletonClass object won't be created every time (even if "singleton" is not null). It will be created only in case when value of "singleton" equals null. In MSDN pages related to entire family of this method, "Remarks" section says: "If comparand and location1 are equal, then value is stored in the destination. Otherwise, no operation is performed." I hope that "not operation is performed" assumes and no creating a new instance of singleton class (which would be totally unnecessary).

At the end of this article http://msdn2.microsoft.com/en-us/library/f857xew0(VS.71).aspx there's code equivalent to Interlocked.CompareExchange Method.

Hey anh Thi, how have u been .Should you rename th...

2007-05-11T10:53:00.000+07:00

Hey anh Thi, how have u been .

Should you rename this blog "title" to "A glass of wine" ?

That is so right. I have felt the same. In fact to...

2005-12-21T15:47:00.000+07:00

That is so right. I have felt the same. In fact to the extent that in one project when designers explined that new project do not match reqs they cancelled the whole project and kept on using old system for next 2 years. That was in 2002.

AD (SDE)

Are there any other blogs about your tropic? ...

2005-11-02T12:38:00.000+07:00

Are there any other blogs about your tropic? -----------------------------------------------------------------------------imitrex-supplier prescription