🚀 go-pugleaf

"Nate Lockwood" <RNLockwoodREMOVE@attglobal.net> wrote in message
news:44021981$1@newsgroups.borland.com...

> Here is some code

Your code is still incorrect for several reasons:

1) you are accessing a NULL TStringList pointer when constructing the
message to be sent

2) you are never checking the WM_MYMSG global for 0 before using it, in case
RegisterWindowMessage() fails

3) you are still not freeing the mutex properly.

4) you are still catching the message in the completely wrong place (I
explained that to you earlier).


Use this code instead:

    UINT WM_MYMSG = 0;

    HANDLE CheckForInstance(const AnsiString &sTitle, TStrings *FileList)
    {
        ::SetLastError(0);

        HANDLE hMutex ::CreateMutex(NULL, TRUE,
"USDA.FS.FireScience.GooleEarthTool.mutex");
        if( hMutex != NULL ) // exists or created
        {
            if( ::GetLastError() != ERROR_ALREADY_EXISTS )
                return hMutex;

            if( (WM_MYMSG != 0) && (FileList != NULL) )
            {
                HWND hReceiver  = ::FindWindow("TApplication",
sTitle.c_str());
                if( hReceiver != NULL )
                {
                    AnsiString sBuf = FileList->Text;

                    COPYDATASTRUCT cds = {0};
                    cds.dwData = WM_MYMSG;
                    cds.cbData = sBuf.Length();
                    cds.lpData = pBuf.c_str();

                    ::SendMessage(hReceiver, WM_COPYDATA,
reinterpret_cast<WPARAM>(Application->Handle),
reinterpret_cast<LPARAM>(&cds));
                }
            }

            ::CloseHandle(hMutex);
        }

        return NULL;
    }

    WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
    {
        const AnsiString sTitle = "Google Earth (C) Tool";
        WM_MYMSG =
RegisterWindowMessage("USDA.FS.FireScience.GooleEarthTool.Awake");

        TStringList * FileList = NULL;
        try
        {
            FileList = new TStringList;
            // fill FileList as needed ...

            HANDLE mutex = CheckForInstance(sTitle, FileList);
            if( mutex != NULL )
            {
                Application->Title = """;
                Application->Title = sTitle;
                Application->Initialize();
                Application->CreateForm(__classid(TFormMain), &FormMain);
                Application->CreateForm(__classid(TAboutBox), &AboutBox);
                Application->Run();
            }
        }
        catch (Exception &exception)
        {
            Application->ShowException(&exception);
        }
        catch (...)
        {
            try
            {
                throw Exception("");
            }
            catch (Exception &exception)
            {
                Application->ShowException(&exception);
            }
        }

        if (mutex != NULL)
            ::CloseHandle(mutex);

        return 0;
    }


    extern UINT WM_MYMSG;

    __TFormMain::TFormMain(TComponent *Owner)
        : TForm(Owner)
    {
        Application->HookMainWindow(AppMessageHook);
    }

    __TFormMain::~TFormMain()
    {
        Application->UnhookMainWindow(AppMessageHook);
    }

    bool __fastcall TFormMain::AppMessageHook(TMessage &Message)
    {
        if( Message.Msg == WM_COPYDATA )
        {
            LPCOPYDATASTRUCT lpcds =
reinterpret_cast<LPCOPYDATASTRUCT>(Message.LParam);
            if( (lpcds->dwData == WM_MYMSG) && (WM_MYMSG != 0) )
            {
                AnsiString sData(static_cast<char*>(lpcds->lpData),
lpcds->cbData);
                // use sData as needed ...
                Application->Restore();
                Show();
                return true;
            }
        }
        return false;
    }


Gambit