#include <stdlib.h>#include <gtk/gtk.h>static void selection_received( GtkWidget        *widget,                                 GtkSelectionData *selection_data,                                 gpointer          data );/* Signal handler invoked when user clicks on the "Get Targets" button */static void get_targets( GtkWidget *widget,                         gpointer data ){  static GdkAtom targets_atom = GDK_NONE;  GtkWidget *window = (GtkWidget *)data;	  /* Get the atom corresponding to the string "TARGETS" */  if (targets_atom == GDK_NONE)    targets_atom = gdk_atom_intern ("TARGETS", FALSE);  /* And request the "TARGETS" target for the primary selection */  gtk_selection_convert (window, GDK_SELECTION_PRIMARY, targets_atom,			 GDK_CURRENT_TIME);}/* Signal handler called when the selections owner returns the data */static void selection_received( GtkWidget        *widget,                                GtkSelectionData *selection_data,                                 gpointer          data ){  GdkAtom *atoms;  GList *item_list;  int i;  /* **** IMPORTANT **** Check to see if retrieval succeeded  */  if (selection_data->length < 0)    {      g_print ("Selection retrieval failed\n");      return;    }  /* Make sure we got the data in the expected form */  if (selection_data->type != GDK_SELECTION_TYPE_ATOM)    {      g_print ("Selection \"TARGETS\" was not returned as atoms!\n");      return;    }    /* Print out the atoms we received */  atoms = (GdkAtom *)selection_data->data;  item_list = NULL;  for (i = 0; i < selection_data->length / sizeof(GdkAtom); i++)    {      char *name;      name = gdk_atom_name (atoms[i]);      if (name != NULL)	g_print ("%s\n",name);      else	g_print ("(bad atom)\n");    }  return;}int main( int   argc,          char *argv[] ){  GtkWidget *window;  GtkWidget *button;    gtk_init (&argc, &argv);  /* Create the toplevel window */  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);  gtk_window_set_title (GTK_WINDOW (window), "Event Box");  gtk_container_set_border_width (GTK_CONTAINER (window), 10);  g_signal_connect (G_OBJECT (window), "destroy",	            G_CALLBACK (exit), NULL);  /* Create a button the user can click to get targets */  button = gtk_button_new_with_label ("Get Targets");  gtk_container_add (GTK_CONTAINER (window), button);  g_signal_connect (G_OBJECT (button), "clicked",		    G_CALLBACK (get_targets), (gpointer) window);  g_signal_connect (G_OBJECT (window), "selection_received",		    G_CALLBACK (selection_received), NULL);  gtk_widget_show (button);  gtk_widget_show (window);    gtk_main ();    return 0;}