[rtems commit] basedefs.h: Add RTEMS_COMPILER_UNUSED_ATTRIBUTE.

[Joel Sherrill]

Module:    rtems
Branch:    master
Commit:    ecd82b6def40960e168ccb3d4b19ce32fab2d989
Changeset: http://git.rtems.org/rtems/commit/?id=ecd82b6def40960e168ccb3d4b19ce32fab2d989

Author:    Joel Sherrill <joel.sherrill at oarcorp.com>
Date:      Sun Sep 22 09:40:44 2013 -0500

basedefs.h: Add RTEMS_COMPILER_UNUSED_ATTRIBUTE.

---

 cpukit/score/include/rtems/score/basedefs.h |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/cpukit/score/include/rtems/score/basedefs.h b/cpukit/score/include/rtems/score/basedefs.h
index 858ca93..082bfbd 100644
--- a/cpukit/score/include/rtems/score/basedefs.h
+++ b/cpukit/score/include/rtems/score/basedefs.h
@@ -184,6 +184,17 @@
   #define RTEMS_COMPILER_DEPRECATED_ATTRIBUTE
 #endif
 
+/**
+ *  Instructs the compiler that a specific variable is deliberately unused.
+ *  This can occur when reading volatile device memory or skipping arguments
+ *  in a variable argument method.
+ */
+#if defined(__GNUC__)        
+  #define RTEMS_COMPILER_UNUSED_ATTRIBUTE __attribute__((unused))
+#else
+  #define RTEMS_COMPILER_UNUSED_ATTRIBUTE
+#endif
+
 #if __cplusplus >= 201103L
   #define RTEMS_STATIC_ASSERT(cond, msg) \
     static_assert(cond, # msg)