Re: [Gtk2forpascal-devel] Why my program crash?

[Mattias G. <nc-...@ne...>]

On Tue, 22 Oct 2002 17:24:50 +0800
mili <mil...@16...> wrote:

> Hello, Every one
>   My program appears weild. Can anybody find the solutions for them?
>   (1)First problem:
>     Compile and run the test program, and try to enter some chars into
>     the 
> textviewer, then you will find that the codes under "//---1" can
> correctly output chars you entered, but the codes under "//---2" can't
> give correct results, and sometimes cause the program to crash. I
> suspect that the system has not regard "texts: String" as a String but
> a PChar.

gtk does not know strings. 'texts' must be a PChar. And PChar begins at
0 not at 1 like strings.

hope this helps,
Mattias



> 
>   (2)Second problem:
>     Now comment the codes under "//---2" so that we can test the
>     program. Then try to enter some chars, almost all chars will not
>     cause problems, 
> but as soon as you press the key of "enter", the program crashes!!!
>     So perhaps it's the signal & it's handler of "insert_text" that
>     should be 
> responsible for these problems. It's very possible that there's a bug
> in Gtk2forpascal.
> 
>   Thanks,
>   Yours,
>   mili
> 
> >>>>>>>>
> 
> program test;
> 
> {$mode objfpc} {$H+}
> 
> uses
>   glib2, gtk2, gdk2;
> 
> var
>   window : PGtkWidget;
>   sw     : PGtkWidget;
>   tv     : PGtkWidget;
>   buffer : PGtkTextBuffer;
> 
> procedure destroy (window: PGtkWidget; data: gpointer); cdecl;
> begin
>    gtk_main_quit();
> end;//destroy
> 
> procedure InsertTextHandler(buffer: PGtkTextBuffer; pos: PGtkTextIter;
>   texts: String; len: gint; um: gpointer); cdecl;
> var
>   str:String;
>   i  :Integer;
> begin
>   //Actually, I did nothing in this handler
>   writeln('@ InsertTextHandler');
>   //---1
>   setlength(str,len);
>   for i:=1 to len do str[i]:=texts[i];
>   writeln('String: ', str);
>   //---2
>   writeln('String: ', texts);
> end;//InsertTextHandler
> 
> begin
>   gtk_init(@argc,@argv);
> 
>   window:=gtk_window_new(GTK_WINDOW_TOPLEVEL);
>   gtk_widget_set_size_request(window,500,400);
>   gtk_window_set_position(PGtkWindow(window),GTK_WIN_POS_CENTER_ALWAY
>   S); gtk_window_set_title(PGtkWindow(window),'Test');
>   g_signal_connect(window,'destroy',TGCallback(@destroy),NULL);
> 
>   sw:=gtk_scrolled_window_new(NULL,NULL);
>   tv:=gtk_text_view_new();
>   buffer:=gtk_text_view_get_buffer(PGtkTextView(tv));
>   g_signal_connect(PGOBJECT(buffer), 'insert_text',
>     TGCallback(@InsertTextHandler), nil);
>   gtk_container_add(PGtkContainer(sw),tv);
>   gtk_widget_show(tv);
>   gtk_widget_show(sw);
>   gtk_container_add(PGtkContainer(window),sw);
> 
>   gtk_widget_show(window);
>   gtk_main();
> end.//test
> 
> <<<<<<<<
> 
> 
> 
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