🚀 go-pugleaf

Hi Robert
 
 Robert Huang says:
 
> When A is running, the message "Already in running!!" will appear.
> But when A is terminated, the message will still appear.
> How do I fix the problem?

The corrections in the code below is just an idea, 
and I have not tested it.

Kind regards
Asger

//---------------------------------------------------------------------------
void __fastcall TBForm::ButtonExeClick(TObject *Sender)
{
    HANDLE TargetMutex = CreateMutex(NULL, false, "Program-A");
    if(GetLastError() == ERROR_ALREADY_EXISTS)
    {
       ShowMessage("Already in running!!");
    }else 
    if(TargetMutex){
       ReleaseMutex(TargetMutex);
       CloseHandle(TargetMutex);
	 WinExec(ExeATitle.c_str(), SW_SHOW);
    }     
}
//---------------------------------------------------------------------------


And in program-A will be like this:


HANDLE Mutex;
//---------------------------------------------------------------------------
__fastcall TAForm::TAForm(TComponent* Owner)
        : TForm(Owner)
{
    Mutex = CreateMutex(NULL, false, "Program-A");
   // shouldn't You be doing some checking here ??
}
//---------------------------------------------------------------------------
void __fastcall TAForm::FormClose(TObject *Sender, TCloseAction &Action)
{
    ReleaseMutex(Mutex);
    CloseHandle(Mutex);
    Action = caFree;
}
//---------------------------------------------------------------------------

Thank you for your suggestion:)
It work!! 

"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);
    }


Gambit