[lazarus] Learning component building blocks

[Payne Thomas E CNIN]

This is way off the latest discussions, but I am trying things on the ground
floor.
I am aiming at using FPC and LAZARUS in the real world when they are done,
but at the moment I am trying to learn how to use the basic tools, at hopes
to
contribute for everyones benefit.

My simple program below was attempting to mix serial comm with a GTK gui.  I

can talk through the serial port OK by itself.  I can get the buttons to
work by 
themselves.  But when I add any gtk calls to the basic serial I/O it behaves

abnormally.

Anyone have a clue why gtk would interfere with the serial port?

Tom
_______________________________________________________________
      Program tdc1;

      Uses linux,glib,gdk,gtk,sysutils;

      Const myLine : String[80] = #128#00#03#21#12#164;

      Var myFD : Longint;

      procedure lcp_status_command( widget : pGtKWidget; 
									data
: gpointer); cdecl;
      begin
          writeln('sending the command');
          if length(myLine)<>fdwrite (myFD,myLine[1],
	
Length(myLine)) then
            Writeln ('Error when writing to file !');
      end;

      procedure quit_program( widget : pGtkWidget; event : pGdkEvent;
                               data : gpointer); cdecl;
      begin
          fdClose(myFD);
          gtk_main_quit();
      end;

      var
        window, button, box1 : pGtkWidget;

      begin
        myFD:=fdOpen ('/dev/cua0',Open_WrOnly);  //from fdopen example in
FPC
        if myFD>0 then
          begin

          if length(myLine)<>fdwrite (myFD,myLine[1],
			Length(myLine)) then
            Writeln ('Error when writing to file !');

{         //Taken from GTK 1.2 tutorial, section 3.3, and converted to .pp
          //* This is called in all GTK applications. Arguments are
          // parsed
          // * from the command line and are returned to the
          // application. */
          gtk_init (@argc, @argv);

          //* Create a new window */
          window := gtk_window_new (GTK_WINDOW_TOPLEVEL);

          //* This is a new call, this just sets the title of our
          // * new window to "Hello Buttons!" */
          gtk_window_set_title (GTK_WINDOW (window), 'Hello Buttons!');

          //* Here we just set a handler for delete_event that
          // immediately
          // * exits GTK. */
          gtk_signal_connect (GTK_OBJECT (window), 'delete_event',
                              GTK_SIGNAL_FUNC (@quit_program), NULL);

          //* Sets the border width of the window. */
          gtk_container_set_border_width (GTK_CONTAINER (window), 10);

          //* We create a box to pack widgets into.  This is described
          // in detail
          // * in the "packing" section. The box is not really visible,
          // it
          // * is just used as a tool to arrange widgets. */
          box1 := gtk_hbox_new(FALSE, 0);

          //* Put the box into the main window. */
          gtk_container_add (GTK_CONTAINER (window), box1);

          //* Creates a new button with the label "Button 1". */
          button := gtk_button_new_with_label ('Button 1');

          //* Now when the button is clicked, we call the "callback"
          // function
          // * with a pointer to "button 1" as its argument */
          gtk_signal_connect (GTK_OBJECT (button), 'clicked',
                              GTK_SIGNAL_FUNC (@lcp_status_command),
                                                               Nil);

          //* Instead of gtk_container_add, we pack this button into the
          //  invisible
          //  * box, which has been packed into the window. */
          gtk_box_pack_start(GTK_BOX(box1), button, TRUE, TRUE, 0);

          //* Always remember this step, this tells GTK that our
          // preparation for
          // * this button is complete, and it can now be displayed. */
          gtk_widget_show(button);

          //* Do these same steps again to create a second button */
          button := gtk_button_new_with_label ('Button 2');

          //* Call the same callback function with a different argument,

          // * passing a pointer to "button 2" instead. */
          gtk_signal_connect (GTK_OBJECT (button), 'clicked',
                              GTK_SIGNAL_FUNC (@lcp_status_command),
                                                              Nil);

          gtk_box_pack_start(GTK_BOX(box1), button, TRUE, TRUE, 0);

          //* The order in which we show the buttons is not really
          //   important, but I
          // * recommend showing the window last, so it all pops up at
          // once. */
          gtk_widget_show(button);

          gtk_widget_show(box1);

          gtk_widget_show (window);

          //* Rest in gtk_main and wait for the fun to begin! */
          gtk_main ();
}

          end
   else
            writeln('Error opening File');
      end.