Permit aliasing of pointers to wimp_window_state and wimp_open.

svn path=/trunk/netsurf/; revision=6944

1 files changed, 38 insertions, 0 deletions

diff --git a/riscos/wimputils.h b/riscos/wimputils.h
new file mode 100644
index 000000000..5a6349b9f
--- /dev/null
+++ b/riscos/wimputils.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2009 John-Mark Bell <jmb@netsurf-browser.org>
+ *
+ * This file is part of NetSurf, http://www.netsurf-browser.org/
+ *
+ * NetSurf is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * NetSurf is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** \file
+ * A collection of grubby utilities for working with OSLib's wimp API.
+ */
+
+#ifndef riscos_wimputils_h_
+#define riscos_wimputils_h_
+
+#include <oslib/wimp.h>
+
+/* Magical union for working around strict aliasing 
+ * Do not use this directly. Use the macros, instead. */
+typedef union window_open_state {
+	wimp_window_state state;
+	wimp_open open;
+} window_open_state;
+
+/* Convert a pointer to a wimp_window_state into a pointer to a wimp_open */
+#define PTR_WIMP_OPEN(pstate) ((wimp_open *) (window_open_state *) (pstate))
+
+#endif