[Mono-list] howto don't allow to execute program two times?

[Xavi de Blas]

Thanks Eric, this will be nice if it's ported to Mono.

Now i think i will create a file when it's running. And delete when
program exits.
Everytime that program starts i will see if file is created. And if
it's created it will ask the user if it has two instances or if
program crashed.

Is not perfect but i hope it works

Thanks again


2007/9/19, Engler, Eric <Eric.Engler at zcsterling.com>:
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> I am not doing this in Mono yet, but here's the code I have for Windows.
>
> This code came from here:
> http://www.personalmicrocosms.com/html/dotnettips.html
>
> The first function detects if another instance is running. The caller of
> this function can then take action: typically he'll just end his own
> program. Or he may want to pop-up the other instance that's already
> running before he exits (far less portable - see below).
>
> This function uses a Mutex, which may be portable to Mono:
>
> private static Mutex mutex = null;
>
> // Determine if the current process is already running
> public static bool ThisProcessIsAlreadyRunning()
> {
>   // Only want to call this method once, at startup.
>   Debug.Assert(mutex == null);
>   // createdNew needs to be false in .Net 2.0, otherwise, if another
> instance of
>   // this program is running, the Mutex constructor will block, and then
> throw
>   // an exception if the other instance is shut down.
>   bool createdNew = false;
>   mutex = new Mutex(false, "PgmName Mutex", out createdNew);
>
>   Debug.Assert(mutex != null);
>   return !createdNew;
> }
>
> Here's the Windows code that can be used to pop-up the other instance.
> This is full of non-portable API calls, so I hope someone can help to
> make these work with Mono:
>
>   [DllImport("user32.dll", SetLastError = true)]
>   static extern int FindWindow(string lpClassName, string lpWindowName);
>
>   [DllImport("user32.dll")]
>   [return: MarshalAs(UnmanagedType.Bool)]
>    static extern bool SetForegroundWindow(int hWnd);
>
>   [DllImport("user32.dll")]
>   static extern bool IsIconic(int hWnd);
>
>   [DllImport("user32.dll")]
>   static extern bool ShowWindow(int hWnd, int nCmdShow);
>
>   const int SW_RESTORE = 9;
>
>   [DllImport("user32.dll")]
>   static extern int GetLastActivePopup(int hWnd);
>
>   [DllImport("user32.dll")]
>   static extern bool IsWindowEnabled(int hWnd);
>
>   // Set focus to the previous instance of the specified program.
>   public static void SetFocusToPreviousInstance(string windowCaption)
>   {
>      // Look for previous instance of this program.
>      int hWnd = FindWindow(null, windowCaption);
>      // If a previous instance of this program was found...
>      if (hWnd != 0)
>      {
>          // Is it displaying a popup window?
>          int hPopupWnd = GetLastActivePopup(hWnd);
>          // If so, set focus to the popup window. Otherwise set focus
>          // to the program's main window.
>          if (hPopupWnd != 0 && IsWindowEnabled(hPopupWnd))
>          {
>             hWnd = hPopupWnd;
>          }
>          SetForegroundWindow(hWnd);
>          // If program is minimized, restore it.
>          if (IsIconic(hWnd))
>          {
>            ShowWindow(hWnd, SW_RESTORE);
>          }
>      }
>   }
>
>
>
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