?
Solved

Synchronization between instances of same processes using CreateEvent

Posted on 2014-03-19
1
Medium Priority
?
338 Views
Last Modified: 2014-03-27
Hello experts

I have a problem when synchronizing the same instances of a process. My application will call from other jobs simultaneously , it instantiate the multiple instances of the application.

 I want to create a event in the application and signal it  after completion of one instance I will un-signal it,  other instances should instances should wait until first completes.

created sample code. but it is in infinite loop.

            HANDLE  hEvent1 = CreateEvent ( NULL , true , false , L"MyEvent" );
            hEvent = OpenEvent ( EVENT_ALL_ACCESS , false, L"MyEvent" );
            if(GetLastError () == ERROR_ALREADY_EXISTS)
            {
                  while (WaitForSingleObject(hEvent,INFINITE)==WAIT_OBJECT_0)
                  {
                        Sleep(0);
                  }
                  SetEvent (hEvent);
            }
            else
                  SetEvent (hEvent );




//in the ending of application.
ResetEvent (hEvent);


Please advise
Thanks in advance
0
Comment
Question by:HarishMinu
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 35

Accepted Solution

by:
sarabande earned 2000 total points
ID: 39944788
HANDLE  hEvent1 = CreateEvent ( NULL , true , false , L"MyEvent" );
 hEvent = OpenEvent ( EVENT_ALL_ACCESS , false, L"MyEvent" );

I would assume that the second call would return with success but has the GetLastError as ERROR_ALREADY_EXIST. then you wait infinite on the event created by the instance itself.

you would either need to pass the EVENT_ALL_ACCESS with the CreateEvent and omit the OpenEvent call (note the CreateEvent would also work for an already created event and would return a valid handle).  or you would check the GetLastError before calling OpenEvent. I would prefer the first alternative.

Sara
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

If you have ever found yourself doing a repetitive action with the mouse and keyboard, and if you have even a little programming experience, there is a good chance that you can use a text editor to whip together a sort of macro to automate the proce…
For most people, the WrapPanel seems like a magic when they switch from WinForms to WPF. Most of us will think that the code that is used to write a control like that would be difficult. However, most of the work is done by the WPF engine, and the W…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
In this video you will find out how to export Office 365 mailboxes using the built in eDiscovery tool. Bear in mind that although this method might be useful in some cases, using PST files as Office 365 backup is troublesome in a long run (more on t…

741 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question