gtk+ 3.x key bindings - struggling - c

Question

I've tried a few things and may be nearing a solution but here goes ...
on a (possibly realised) widget, has anyone got a good example of say an
GtkEntry widget receiving a ALT+ Down or CTRL + n key press which will raise
a "new" signal e.g. SIG-NEW on the widget. which I know how to catch with g_signal_connect.

Answer 1

I appended a minimal working example.
The important point is to connect the key-press-event of an GtkEntry-instance to a suitable callback. In that callback you have to extract the GdkEventKey struct that is a member of the GdkEvent struct which is a parameter of the callback function.
GdkEventKey contains all information you need to check which key+modifier was pressed.
Since i tested the code with gtk+-3.0 you may have to modify the GdkEventMask of the widget to receive key-press-event's. For gtk+-3.0 it seems that is already the default setting. If the callback isn't invoked you should enable it with gdk_window_set_events () (of course you have to invoke it upon the gdk window of the widget).
#include <gtk/gtk.h>
#include <glib.h>
gboolean
key_press_event_cb (GtkWidget * widget, GdkEvent * event,
gpointer data)
{
GdkEventKey key = event->key;
/* check modifier key */
/* on most keyboards GDK_MOD1_MASK is the Alt key */
if (key.state == GDK_MOD1_MASK) {
/* check for key that was pressed */
switch (key.keyval) {
case GDK_KEY_d:
g_print
("`Alt-d` deletes the content in the entry box\n");
gtk_entry_set_text (GTK_ENTRY (widget), "");
break;
}
}
/* check for unmodified key presses */
switch (key.keyval) {
case GDK_KEY_x:
g_print
("`x` deletes the content in the entry box\n");
gtk_entry_set_text (GTK_ENTRY (widget), "");
return TRUE;
break;
}
return FALSE;
}
int
main (int argc, char *argv[])
{
GtkWidget *window;
GtkWidget *entry;
gtk_init (&argc, &argv);
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
entry = gtk_entry_new ();
gtk_container_add (GTK_CONTAINER (window), entry);
gtk_widget_show_all (window);
g_signal_connect (window, "destroy",
G_CALLBACK (gtk_main_quit), NULL);
g_signal_connect (entry, "key-press-event",
G_CALLBACK (key_press_event_cb), NULL);
gtk_main ();
return 0;
}