gtk+ vte scrollback not working - c

Question

gtk+ ver 2.24.8
vte ver 0.28.2
I just starting out creating a terminal application, however, none of the examples I have found online (5) have working scrollback. Is there a problem with scrollback in vte or is it something I'm not seeing? Here is one example:
#include <gtk/gtk.h>
#include <vte/vte.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <gdk/gdkkeysyms.h> // includes GDK_q
/* gcc -Wall -g term.c -o term `pkg-config --cflags --libs gtk+-2.0 vte` */
long size;
char *buf;
char *ptr;
gboolean key_press_win_main (GtkWidget *widget, GdkEventKey *event, gpointer user_data);
void quit_activated();
static gboolean delete_event(GtkWidget *,GdkEvent *);
int main( int argc, char *argv[] )
{
size = pathconf(".", _PC_PATH_MAX);
if ((buf = (char *)malloc((size_t)size)) != NULL) ptr = getcwd(buf, (size_t)size);
GtkWidget *window_main;
GtkWidget *vbox;
GtkWidget *vte;
GtkWidget *notebook;
GtkWidget *scrolled_window;
GtkWidget *label;
gtk_init (&argc, &argv);
window_main = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title (GTK_WINDOW (window_main), "Caraterm v0.0.1");
vbox = gtk_vbox_new(FALSE,0);
gtk_container_add (GTK_CONTAINER (window_main), vbox);
notebook = gtk_notebook_new ();
gtk_notebook_set_tab_pos (GTK_NOTEBOOK (notebook), GTK_POS_BOTTOM);
gtk_box_pack_start (GTK_BOX (vbox), notebook, TRUE, TRUE, 0);
scrolled_window = gtk_scrolled_window_new (NULL, NULL);
gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_window), GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC);
label = gtk_label_new ("term1");
gtk_notebook_append_page (GTK_NOTEBOOK (notebook), scrolled_window, label);
vte = vte_terminal_new();
vte_terminal_set_background_transparent(VTE_TERMINAL(vte), FALSE);
vte_terminal_set_size(VTE_TERMINAL(vte), 80, 45);
vte_terminal_set_scrollback_lines(VTE_TERMINAL (vte), -1); /* infinite scrollback */
vte_terminal_fork_command(VTE_TERMINAL(vte), NULL, NULL, NULL, ptr, TRUE, TRUE,TRUE);
vte_terminal_set_scroll_on_keystroke(VTE_TERMINAL (vte), TRUE);
gtk_scrolled_window_add_with_viewport (GTK_SCROLLED_WINDOW (scrolled_window), vte);
printf("%s\n", vte_terminal_get_emulation(VTE_TERMINAL (vte)));
g_signal_connect(G_OBJECT(window_main),"destroy",G_CALLBACK(quit_activated),NULL);
g_signal_connect(G_OBJECT(window_main),"delete_event",G_CALLBACK(delete_event),NULL);
g_signal_connect (G_OBJECT (window_main), "key_press_event", G_CALLBACK (key_press_win_main), NULL);
gtk_widget_show (label);
gtk_widget_show (notebook);
gtk_widget_show (scrolled_window);
gtk_widget_show (vte);
gtk_widget_show (vbox);
gtk_widget_show (window_main);
gtk_main ();
return 0;
}
gboolean key_press_win_main (GtkWidget *widget, GdkEventKey *event, gpointer user_data)
{
switch (event->keyval)
{
case GDK_q:
if (event -> state & GDK_CONTROL_MASK)
{
printf("entered q\n");
quit_activated();
}
break;
default:
return FALSE;
}
return FALSE;
}
void quit_activated()
{
gtk_main_quit();
}
static gboolean delete_event(GtkWidget *window_main,GdkEvent *event)
{
return FALSE;
}
This example will scroll but only to accomodate the original size of the vte set via vte_terminal_set_size(VTE_TERMINAL(vte), 80, 45); If more lines are added to the terminal by simply hitting return or producing output from a program the scrollback buffer does not expand. It is fixed at 45 lines despite the fact that an unlimited scrollback was specified vte_terminal_set_scrollback_lines(VTE_TERMINAL (vte), -1); /* infinite scrollback */
What am I missing? Thanks.

Answer 1

In order to get scrollback to work the line that needed to be changed was:
scrolled_window = gtk_scrolled_window_new (NULL, NULL);
to:
scrolled_window = gtk_scrolled_window_new (NULL, terminal->adjustment);
where terminal is defined as:
VteTerminal *terminal;
vte = vte_terminal_new();
terminal = VTE_TERMINAL (vte);

Answer 2

I'm not all that confident since I haven't worked with VTE before. However, it looks like the vte_terminal is itself a scrollable widget. I'd suggest you try to get rid of the scrolled_window and see.
Also, here is what I've found as an example.

Answer 3

try this it's works
//gtk_scrolled_window_add_with_viewport (GTK_SCROLLED_WINDOW (scrolled_window), vte);
gtk_container_add (GTK_CONTAINER(scrolled_window),vte);