Disable double execution of a program

I am writing an MFC dialog based program, and wouldn't like the user to open multiple copies of the program at once.
(only one at a time).
How is this done?
Thanks
gilbert_changAsked:
Who is Participating?
 
alexoConnect With a Mentor Commented:
Details in my comment from December 29 1998 - 05:29AM
0
 
The_BrainCommented:
Do you want only the user to use that program ONLY, or what?
If it is the only application that needs attention then you could force the cursor to remain within the dialog, else you could use a detect which I am not fimiliar with.  (All though I would prob. say don't open two apps.

I would write a file which holds a value 1 or 0, and that will tell me if the application is allready running.

when you are in INITDialog read the value and use

if (!value)
   return;

this will quit the second app before it even comes up.  hope this helps.
0
 
The_BrainCommented:
Do you want only the user to use that program ONLY, or what?
If it is the only application that needs attention then you could force the cursor to remain within the dialog, else you could use a detect which I am not fimiliar with.  (All though I would prob. say don't open two apps.

I would write a file which holds a value 1 or 0, and that will tell me if the application is allready running.

when you are in INITDialog read the value and use

if (!value)
   return;


You will say on Create, make value=1 and writeover the file.
and at the end rewrite to 0.
this will quit the second app before it even comes up.  hope this helps.
0
Cloud Class® Course: Microsoft Office 2010

This course will introduce you to the interfaces and features of Microsoft Office 2010 Word, Excel, PowerPoint, Outlook, and Access. You will learn about the features that are shared between all products in the Office suite, as well as the new features that are product specific.

 
The_BrainCommented:
if you want me to eleb, then I will, but just create a file and add char Value=1;  when the app starts.  (OnCreate)
then when it closes (fp.write("0");  (something to that effect);


0
 
alexoCommented:
Here is the "official" way of limiting a program to only one instance:

    // Beginning of program
    HANDLE hMutex;
    hMutex = CreateMutex(NULL, FALSE, "Some unique string");
    if (GetLastError() == ERROR_ALREADY_EXISTS)
    {
        // Application already running, display an error or something
        CloseHandle(hMutex);
        return 0;
    }

    // The rest of the program goes here...

    // End of program
    CloseHandle(hMutex);
    return 1;

If this is what you need, you'll need to reject the currently pending answer so you can accept mine.
0
 
gilbert_changAuthor Commented:
alexo's answer works great. Thanks The_Brain too.
0
 
gilbert_changAuthor Commented:
Thanks.
0
 
gilbert_changAuthor Commented:
Thanks.
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.