🚀 go-pugleaf

"Robert Huang" <remmurds.bbs@ptt.cc> wrote in message 
news:47817e00@newsgroups.borland.com...

>    ReleaseMutex(Mutex);

That will not free the mutex.  It will only release the lock that program A 
may have on it.  You need to use CloseHandle() to actually free the mutex.

> When A is running, the message "Already in running!!" will
> appear. But when A is terminated, the message will still appear.

Neither program A or B are closing their respective handles to the mutex. 
All calls to Create/OpenMutex() must be balanced with equal calls to 
CloseHandle().  Since program B is not closing its handle to the mutex, the 
mutex remains alive after program A has terminated.

    void __fastcall TBForm::ButtonExeClick(TObject *Sender)
    {
        HANDLE TargetMutex = OpenMutex(SYNCHRONIZE, FALSE, "Program-A");
        if( !TargetMutex )
            WinExec(ExeATitle.c_str(), SW_SHOW);
        else
        {
            CloseHandle(TargetMutex); // <-- add this!
            ShowMessage("Already in running!!");
        }
    }


    __fastcall TAForm::TAForm(TComponent* Owner)
        : TForm(Owner)
    {
        Mutex = CreateMutex(NULL, FALSE, "Program-A");
    }

    __fastcall TAForm::~TAForm()
    {
        CloseHandle(Mutex);
    }


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