title: g_signal_connect error invalid use of member
body: <p>I'm trying to compile some code and I'm getting the following error:</p>
  
  <pre><code>error: invalid use of member (did you forget the ‘&amp;’ ?)
  </code></pre>
  
  <p>This is coming from the g_signal_connect call:</p>
  
  <pre><code>g_signal_connect ((gpointer) Drawing_Area_CPU, "expose-event", 
          G_CALLBACK (graph_expose), NULL);
  </code></pre>
  
  <p><code>Drawing_Area_CPU</code> is a <code>GtkWidget *</code> and <code>graph_expose</code> is defined as:</p>
  
  <pre><code>gboolean graph_expose(GtkWidget *widget, GdkEventExpose *event, gpointer data);
  </code></pre>
  
  <p>So far as i can tell im doing everything right, but still i get this error.  Can anyone help please?</p>
  
  <p>UPDATE:</p>
  
  <p>Sorry guys, i got confused, my <code>graph_expose</code> function is in a class, and I'm trying to do the <code>g_signal_connect</code>s from the constructor of that class, would that affect this problem in any way?</p>