diff --git a/CMakeLists.txt b/CMakeLists.txt
index b1ee902..cc0b54f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -39,8 +39,8 @@ endif(NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
 set(DOXYFILE_LATEX false)
 include(UseDoxygen)
 
-# Compilation
-add_definitions(-Wall)
+# Switch on warnings.
+add_definitions(-Wall -Wextra)
 
 # Boost required for any and cstdint on MSVC < 2010
 find_package(Boost COMPONENTS REQUIRED)
diff --git a/nabo/brute_force_cpu.cpp b/nabo/brute_force_cpu.cpp
index cc3cdce..60a6996 100644
--- a/nabo/brute_force_cpu.cpp
+++ b/nabo/brute_force_cpu.cpp
@@ -68,7 +68,7 @@ namespace Nabo
 	}
 	
 	template<typename T, typename CloudType>
-	unsigned long BruteForceSearch<T, CloudType>::knn(const Matrix& query, IndexMatrix& indices, Matrix& dists2, const Vector& maxRadii, const Index k, const T epsilon, const unsigned optionFlags) const
+	unsigned long BruteForceSearch<T, CloudType>::knn(const Matrix& query, IndexMatrix& indices, Matrix& dists2, const Vector& maxRadii, const Index k, const T /*epsilon*/, const unsigned optionFlags) const
 	{
 		checkSizesKnn(query, indices, dists2, k, optionFlags, &maxRadii);
 		
diff --git a/tests/knnbench.cpp b/tests/knnbench.cpp
index 29e8ea2..b8a8c75 100644
--- a/tests/knnbench.cpp
+++ b/tests/knnbench.cpp
@@ -137,7 +137,7 @@ BenchResult doBenchType(const typename NearestNeighbourSearch<T>::SearchType typ
 						const typename NearestNeighbourSearch<T>::Matrix& d,
 						const typename NearestNeighbourSearch<T>::Matrix& q,
 						const int K,
-						const int itCount,
+						const int /*itCount*/,
 						const int searchCount)
 {
 	typedef NearestNeighbourSearch<T> nnsT;