diff --git a/lib/cpp/src/thrift/Thrift.h b/lib/cpp/src/thrift/Thrift.h
index 03caa9e..7b9a8ad 100644
--- a/lib/cpp/src/thrift/Thrift.h
+++ b/lib/cpp/src/thrift/Thrift.h
@@ -69,7 +69,7 @@
 #define THRIFT_OVERLOAD_IF(T, Y) \
   THRIFT_OVERLOAD_IF_DEFN(T, Y) = NULL
 
-#define THRIFT_UNUSED_VARIABLE(x) ((x)=(x))
+#define THRIFT_UNUSED_VARIABLE(x) ((void)(x))
 
 namespace apache { namespace thrift {
 
diff --git a/lib/cpp/src/thrift/concurrency/BoostMutex.cpp b/lib/cpp/src/thrift/concurrency/BoostMutex.cpp
index eb0c3c1..59c3618 100644
--- a/lib/cpp/src/thrift/concurrency/BoostMutex.cpp
+++ b/lib/cpp/src/thrift/concurrency/BoostMutex.cpp
@@ -21,6 +21,7 @@
 
 #include <thrift/concurrency/Mutex.h>
 #include <thrift/concurrency/Util.h>
+#include <thrift/Thrift.h>
 
 #include <cassert>
 #include <boost/thread.hpp>
@@ -37,7 +38,8 @@
 class Mutex::impl : public boost::timed_mutex {
 };
 
-Mutex::Mutex(Initializer init) : impl_(new Mutex::impl()) {}
+Mutex::Mutex(Initializer init) : impl_(new Mutex::impl())
+{ THRIFT_UNUSED_VARIABLE(init); }
 
 void* Mutex::getUnderlyingImpl() const { return impl_.get(); }
 
@@ -50,7 +52,7 @@
 void Mutex::unlock() const { impl_->unlock(); }
 
 void Mutex::DEFAULT_INITIALIZER(void* arg) {
+  THRIFT_UNUSED_VARIABLE(arg);
 }
 
 }}} // apache::thrift::concurrency
-