Click here to Skip to main content

Article

Single Instance Checker

bigZidane

Rate me:

3.45/5 (10 votes)

17 Apr 2002

95.8K

1.2K

25

20

Only 1 instance of your application can run in the same time

Introduction

If you want your application have just only instance is run in the same time, you only download and use it.

Step 1: Add file "LimitSingleInstance.h" to your project. This file is written by Microsoft. :-)

Step 2: Run UUIDGEN.EXE to get ID. This tool is written by Micorosft :-)

Step 3: Declare a variable

CLimitSingleInstance g_SingleInstanceObj(TEXT("{ID get from UUIDGEN}"));

for ex: CLimitSingleInstance g_SingleInstanceObj(TEXT("{addb6c1d-d98d-40f4-8041-0eb6b8bc884c}"));

Step 4: InitInstance()

Only add this line to check instance and make sure only 1 instance can run.

if (g_SingleInstanceObj.IsAnotherInstanceRunning()) return FALSE;

VERY and VERY SIMPLE.

I get this information and "LimitSingleInstance.h" from KnowledgeBase of Mirosoft site.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

Written By

bigZidane

Web Developer

Vietnam

// -------------------------------- //
// Personal Information //
// -------------------------------- //
Yahoo ID : dothanhtrongnghia
AOL : trongnghia95
ICQ : 151917542
Cell Phone : (84)-(90)-(3329867)

Comments and Discussions

Thanks, bigZidane.

TigerRex1-Nov-14 22:13

1-Nov-14 22:13

Good article. Always good to share info, specially code and coding techniques. And on Code Project!

Mercede15-Oct-09 23:20

15-Oct-09 23:20

this is a word by word copy of microsoft article at http://support.microsoft.com/default.aspx?scid=kb;EN-US;q243953

GoddFadda3-Jan-03 18:04

3-Jan-03 18:04

of whiners... I never knew about this article, so I thank the author for pointing it out. It really did help me. Blush | :O

Blush | :O

Anonymous5-Sep-02 23:51

5-Sep-02 23:51

Whatever it is I like this code and I will use it in my program.
Thanks alot for this code sharing.

winxp, multiple user

19-Apr-02 9:21

19-Apr-02 9:21

i assume this code does not work with multiple users logged in, right?...

in winxp, you can have a program running, do a fast user switch, and run the same program again? i have been trying to do this but the mutex does not seem to work...

Re: winxp, multiple user

Michael Dunn19-Apr-02 11:59

19-Apr-02 11:59

Prefix the mutex name with "Global\" to make it viewable in all user sessions. See MSDN for more details.

--Mike--
Actual sign at the laundromat I go to: "No tinting or dying"
Like the Google toolbar? Then check out UltraBar, with more features & customizable search engines!
My really out-of-date homepage
Big fan of Alyson Hannigan and Jamie Salé.

Re: winxp, multiple user

bigZidane19-Apr-02 17:21

19-Apr-02 17:21

Thanks so much.

What's the point with UUIDGEN.EXE

Ernest Laurentin18-Apr-02 4:44

Ernest Laurentin

18-Apr-02 4:44

What's the point to use UUIDGEN.EXE to create a mutex name since
you may create any other name?
HANDLE hMutex = CreateMutex(NULL, FALSE, _T("MyApplication_MutexName"));
is also valid. Anyway, I still can see a use for it but should we really care!?!?

"Dirty hands lead to important discovery..." - Thomas Edison

Re: What's the point with UUIDGEN.EXE

18-Apr-02 23:35

18-Apr-02 23:35

Easy: Somebody else might accidentally create the same mutex because the application has the same name. In this case, those two applications would not run at the same time.
By using GUID you can be pretty positive, that this does not happen.

Re: What's the point with UUIDGEN.EXE

thenickname10-Apr-05 11:13

10-Apr-05 11:13

Hey, If you can't come up with a name that will be unique you need to take some classes in creativity.

Tim Smith18-Apr-02 4:23

18-Apr-02 4:23

This code won't work if the application can run as a service or interactively.

Tim Smith

I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk?

18-Apr-02 5:55

18-Apr-02 5:55

Hey,
I just want all my friend on another country can get it. Maybe I'm not a good programmer but i want share ....

That's all.

George17-Apr-02 22:28

17-Apr-02 22:28

I am not sure what to say - it seems like the whole article is actually "written by Microsoft" (Q243953), which probably contributes to the poor rating... Confused | :confused:

Confused | :confused:

Actually the MS article is better - it contains one more sample for Win32 SDK application.

So, how about making some more research on the subject, try to explain how exactly it works and then maybe you get more 5s than 1s, because anybody can rip off the code from MSDN and claim to write such an "article" ?

bigZidane17-Apr-02 22:43

17-Apr-02 22:43

uhm...
I just want everybody can find it easily b'cuz many and many person come here to search code.

That's all.

Thanks your comments.

George17-Apr-02 22:52

17-Apr-02 22:52

bigZidane wrote:
I just want everybody can find it easily b'cuz many and many person come here to search code.

Actually come to think of it you should just move the article to the "Programming Tips" section where it seem to belong.

bigZidane17-Apr-02 22:58

17-Apr-02 22:58

I really don't know why you say that. I just want everybody can find it easily.
That's all.

Jim A. Johnson18-Apr-02 4:17

18-Apr-02 4:17

Ditto. It's a waste of space.

18-Apr-02 5:58

18-Apr-02 5:58

I think it did not waste.b'cuz it's too small.

venkpai20-Oct-05 12:47

20-Oct-05 12:47

This article has help me. Smile | :)

Smile | :)

Thanks

Mercede15-Oct-09 23:21

15-Oct-09 23:21

Ditto copy of article at http://support.microsoft.com/default.aspx?scid=kb;EN-US;q243953
perhaps you should take a look at that

General News Suggestion Question Bug Answer Joke Praise Rant Admin

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

Go to top