My application requires the presence of database files. If the user
neglects to ensure these are installed, my program tries to show a
message to that effect and quit gracefully.

However, I get GPF's. I assume the reason is that the functions I call
to display the warning and to test for "FileExists()" are spread in
other units which get created only later. I thought one cannot put the
mainform at the end of the auto-create list. I wonder is there a
graceful way.

Email appreciated. I respond to every email.
Matthew

        I required a similar functionality for an application we designed to aid
in background checks on potential {*word*2} employees.  The tricky part (and
it IS tricky) is to do all your checks in the Application startup code.  To
see this code use View|Project Source.
        There should be several lines of FormCreate and finally a line
"Application.Run".  By instantiating (creating) the units required to
verify startup requirements (in our case password verification, in yours
database presence) and placing a check in the project source you can put
the subsequent FormCreate and Application.Run lines in an if . . then
condition.
        A word of warning.  It is NOT common practice nor is it recommended to
monkey around with the project source.  This can be the cause of many
headaches and late hours.  On the other hand, the benefit of a small, well
thought-out additional amount of code can really flesh out an application.

        If you would like some proven, sample source code, do not hesitate to ask.
 I would have posted some here but I do not have it available to me just
now.

--
Rob Tanner B.E.,B.Sc.
Design Engineer
WestBau Technologies, Inc.

Here's how I've handled a similar need to check for the existence of
key files. The first line in my project source calls a procedure in a
formless error-checking unit. The core code for that unit is as
follows:

  FileList[1] := 'assist96.dat';
  FileList[2] := 'agytot96.dat';
  FileList[3] := 'afdc96.dat';
  FileList[4] := 'census90.dat';
  FileList[5] := 'house96.dat';
  FileList[6] := 'metro.dat';
  FileList[7] := 'metro.cgf';
  FileList[8] := 'metro.cgi';
  FileList[9] := 'metro.cgr';
  GetDir(0,CurDir); {returns the current drive and directory}
  if Length(CurDir) = 3 then  {check if current directory is root
directory}
    CurDirTest := CurDir
  else
    CurDirTest := CurDir + '\';

  for q := 1 to 9 do
    if not FileExists(CurDirTest + FileList[q]) then
    begin
      MessageBeep(mb_ok);
      ShellReturn := MessageDlg('File ' + FileList[q] + ' is
missing.', mtError,[mbOk], 0);
      while GetModuleUsage(ShellReturn) > 0 do
        Application.ProcessMessages;
      Application.Terminate;
      Halt;
    end;

Mark Shapiro
info...@swbell.net

  If FileExists('whatever.db') then Application.Run
  else Exit;  // possibly Application.Terminate;

--
Jason
Dark...@SLSoftware.reno.nv.us

--
Rob Tanner B.E.,B.Sc.
Design Engineer
WestBau Technologies, Inc.

Jason Wallace <Dark...@SLSoftware.reno.nv.us> wrote in article
<333B983A.2...@SLSoftware.reno.nv.us>...

        Application.Initialize;
        Application.Title := 'Insert Title Here';
        Application.CreateForm(TDM, DM);        
        if DM.FileExists('whatever.db' then begin
                Application.CreateForm(TMainForm, MainForm);
                { Create Any Other Forms that are required at startup )
                Application.Run;
        end;

In article <01bc3e23$d80c6640$84c5a...@eweston.wbm.ca> "Rob Tanner" <westbau_technolog...@eagle.wbm.ca> writes:

As-written, the application dies most ungracefully.  In a DLL routine it can
bring down Windows (GPF in DLL).  The problem is that the initialization-code
in the "DB" unit attempts to create a TSession object... blithely assuming
that it will be successful and with no provision to trap an EDBEngineError
exception.

I coded around this (e.g. in ChimneySweep) by creating a local modification to
the DB unit.

With care, you could try putting some test code in the PROJECT SOURCE.
Granted, I've heard that Borland doesn't recommend putting your own code
in the Project source, but I've done it successfully.

Method A)

program Gridtest;

uses
  Forms, sysutils, dialogs,
  Gridtst1 in 'GRIDTST1.PAS' {Form1};

{$R *.RES}

begin
  if not fileexists('c:\idapi\idapi.cfg') then
  begin
   showmessage('You must install the'+#13+
               'Borland Database Engine'+#13+
               'to run this application');
   application.terminate;
  end;
  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.

Method B)

If the BDE might not be in the standard location (different drive,
etc.), you could check the WIN.INI using INIFILES calls.  There is a
Windows API call to identify for the Windows directory in case it is
non-standard.  Anyway, look in the WIN.INI for the appropriate
sections...

[IDAPI]
DLLPATH=C:\IDAPI
CONFIGFILE01=C:\IDAPI\IDAPI.CFG

[Borland Language Drivers]
LDPath=C:\IDAPI\LANGDRV