Callback Funktion programmieren

[paule32.jk]

ich habe eine InitLibrary Funktion, in der der Callback in ein try except Block eingebettet ist:

Delphi-Quellcode:

{$ifdef FPC}
    {$mode delphi}{$H+}
{$else}
    {$APPTYPE CONSOLE}
{$endif}
program fpcqt;
uses
  {$ifdef win64}
  Windows,
  {$endif }
  appsettings in 'pas\appsettings.pas',
  misc in 'pas\misc.pas',
  fpcmain in 'pas\fpcmain.pas',
  QCharClass in 'pas\QCharClass.pas';

procedure EntryPoint(argc: Integer; argv: Array of String);
var
    myQChar: QChar;
begin
    myQChar := QChar.Create;

    if myQChar.isDigit then
    WriteLn('ok') else
    WriteLn('not ok');
    Readln;
    myQChar.Free;
end;

begin
    InitLibrary( EntryPoint );
end.

Delphi-Quellcode:

{$ifdef FPC}
    {$mode delphi}{$H+}
{$endif}
unit misc;

interface
uses
    {$ifdef win64}
    Windows,
    {$endif}
    SysUtils;

const DLLname = 'fpc-qt.dll';
type
    TMainCallback = procedure(argc: Integer; argv: Array of String);

    function InitLibrary(Callback: TMainCallback): Boolean;
    function ErrorMessage(s: AnsiString): Boolean; cdecl; external dllname;

implementation
uses fpcmain;

function InitLibrary(Callback: TMainCallback): Boolean;
begin
  DLLHandle := LoadLibrary('fpc-qt.dll');
  if DLLHandle = 0 then
  begin
    ErrorMessage('Error: DLL could not be loaded.');
    Halt(1);
  end;
  try
    Callback(ParamCount, ParamStr(1));
  finally
      FreeLibrary(DLLHandle);
      ReadLn;
      Halt(0);
  end;
end;

end.