libcsupport: Make LibIO helper const

Add and use rtems_libio_helper function type.  Add and use
rtems_libio_helper_null() instead of NULL pointer.

1 files changed, 30 insertions, 0 deletions

diff --git a/cpukit/libcsupport/src/libio_helper_null.c b/cpukit/libcsupport/src/libio_helper_null.c
new file mode 100644
index 0000000000..17bdb7a557
--- /dev/null
+++ b/cpukit/libcsupport/src/libio_helper_null.c
@@ -0,0 +1,30 @@
+/**
+ * @file
+ *
+ * @ingroup LibIO
+ */
+
+/*
+ * Copyright (c) 2013 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <rtems/libio.h>
+
+void rtems_libio_helper_null(void)
+{
+  /* Do nothing */
+}