Verily, some functions we should have:

You have to #include <gobject/gvaluecollector.h> in the .c file for these.

What think the people?

gboolean
gst_structure_get_valist (GstStructure *s, const char *first_field_name,
                          va_list args)
{
  const char *field_name = first_field_name;

  while (field_name) {
    GType t;
    const GValue *got = NULL;
    gchar *error;

    t = va_arg (args, GType);

    got = gst_structure_get_value (s, field_name);
    if (!got)
      return FALSE;
    if (G_VALUE_TYPE (got) != t)
      return FALSE;
    
    G_VALUE_LCOPY (got, args, 0, &error);
    if (error) {
      g_warning ("%s: %s", G_STRFUNC, error);
      g_free (error);
      return FALSE;
    }

    field_name = va_arg (args, const gchar*);
  }
  
  return TRUE;
}

gboolean
gst_structure_get (GstStructure *s, const char *first_field_name, ...)
{
  gboolean ret;
  va_list args;
  va_start (args, first_field_name);
  ret = gst_structure_get_valist (s, first_field_name, args);
  va_end (args);
  return ret;
}