title: GTK - Cannot print buffer value using function `printf`
body: <p>I get the contents of my <code>textview</code> and I want to display the contents in the terminal using the printf function. But have stange symbols (Why?):</p>
  
  <p><a href="https://i.stack.imgur.com/mIeVo.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mIeVo.png" alt="enter image description here"></a></p>
  
  <pre><code>// get textbuffer from textview end print value in terminal
  void on_lower_button_clicked(GtkWidget *lower_button, GtkTextView *textview_1)
  {
      GtkTextBuffer *textbuffer_1;
      textbuffer_1 = gtk_text_view_get_buffer(GTK_TEXT_VIEW(textview_1));
      printf("%s\n", textbuffer_1); // strange symbols from my buffer ...
  }
  
  int main(int argc, char *argv[])
  {
    GtkWidget *lower_button;
    GtkBuilder *builder;
    GtkWidget *window;
    GError *error = NULL;
  
    gtk_init(&amp;argc, &amp;argv);
  
    builder = gtk_builder_new();
    if(!gtk_builder_add_from_file(builder, "template.ui", &amp;error)) {
      g_printerr("Error loading file: %s\n", error-&gt;message);
      g_clear_error(&amp;error);
      return 1;
    }
  
    window = GTK_WIDGET(gtk_builder_get_object(builder, "window"));
    lower_button = GTK_WIDGET(gtk_builder_get_object(builder, "lower_button"));
  
    gtk_builder_connect_signals(builder, NULL);
    // when I click on the button (lower_button) call 
    // on_lower_button_clicked function and transferred to her textview_1
    g_object_unref(G_OBJECT(builder));
  
    gtk_widget_show(window);
    gtk_main();
  
    return 0;
  }
  </code></pre>