diff --git a/sprout/algorithm/fit/partition_copy.hpp b/sprout/algorithm/fit/partition_copy.hpp
index c9a1f77b..e3a48820 100644
--- a/sprout/algorithm/fit/partition_copy.hpp
+++ b/sprout/algorithm/fit/partition_copy.hpp
@@ -7,7 +7,7 @@
 #include <sprout/algorithm/fixed/partition_copy.hpp>
 #include <sprout/algorithm/fit/result_of.hpp>
 #include <sprout/sub_array.hpp>
-#include <sprout/detail/algorithm_ext.hpp>
+#include <sprout/detail/count_n_if.hpp>
 #include HDR_ALGORITHM_SSCRISK_CEL_OR_SPROUT
 #include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
 
diff --git a/sprout/algorithm/fit/set_difference.hpp b/sprout/algorithm/fit/set_difference.hpp
index e9d759cb..4be4d0a9 100644
--- a/sprout/algorithm/fit/set_difference.hpp
+++ b/sprout/algorithm/fit/set_difference.hpp
@@ -7,7 +7,7 @@
 #include <sprout/algorithm/fixed/set_difference.hpp>
 #include <sprout/algorithm/fit/result_of.hpp>
 #include <sprout/sub_array.hpp>
-#include <sprout/detail/overlap_count_2.hpp>
+#include <sprout/detail/set_overlap_count.hpp>
 #include HDR_ALGORITHM_SSCRISK_CEL_OR_SPROUT
 #include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
 
@@ -30,7 +30,7 @@ namespace sprout {
 					offset,
 					offset + NS_SSCRISK_CEL_OR_SPROUT::min(
 						NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)
-							- sprout::detail::overlap_count_2(first1, last1, first2, last2, comp)
+							- sprout::detail::set_overlap_count(first1, last1, first2, last2, comp)
 							,
 						sprout::size(result)
 						)
@@ -69,7 +69,7 @@ namespace sprout {
 					offset,
 					offset + NS_SSCRISK_CEL_OR_SPROUT::min(
 						NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)
-							- sprout::detail::overlap_count_2(first1, last1, first2, last2)
+							- sprout::detail::set_overlap_count(first1, last1, first2, last2)
 							,
 						sprout::size(result)
 						)
diff --git a/sprout/algorithm/fit/set_intersection.hpp b/sprout/algorithm/fit/set_intersection.hpp
index 9d919fa3..072d3f06 100644
--- a/sprout/algorithm/fit/set_intersection.hpp
+++ b/sprout/algorithm/fit/set_intersection.hpp
@@ -7,7 +7,7 @@
 #include <sprout/algorithm/fixed/set_intersection.hpp>
 #include <sprout/algorithm/fit/result_of.hpp>
 #include <sprout/sub_array.hpp>
-#include <sprout/detail/overlap_count_2.hpp>
+#include <sprout/detail/set_overlap_count.hpp>
 #include HDR_ALGORITHM_SSCRISK_CEL_OR_SPROUT
 
 namespace sprout {
@@ -28,7 +28,7 @@ namespace sprout {
 					sprout::get_internal(sprout::fixed::set_intersection(first1, last1, first2, last2, result, comp)),
 					offset,
 					offset + NS_SSCRISK_CEL_OR_SPROUT::min(
-						sprout::detail::overlap_count_2(first1, last1, first2, last2, comp),
+						sprout::detail::set_overlap_count(first1, last1, first2, last2, comp),
 						sprout::size(result)
 						)
 					);
@@ -65,7 +65,7 @@ namespace sprout {
 					sprout::get_internal(sprout::fixed::set_intersection(first1, last1, first2, last2, result)),
 					offset,
 					offset + NS_SSCRISK_CEL_OR_SPROUT::min(
-						sprout::detail::overlap_count_2(first1, last1, first2, last2),
+						sprout::detail::set_overlap_count(first1, last1, first2, last2),
 						sprout::size(result)
 						)
 					);
diff --git a/sprout/algorithm/fit/set_symmetric_difference.hpp b/sprout/algorithm/fit/set_symmetric_difference.hpp
index 98fd3468..b564e19a 100644
--- a/sprout/algorithm/fit/set_symmetric_difference.hpp
+++ b/sprout/algorithm/fit/set_symmetric_difference.hpp
@@ -7,7 +7,7 @@
 #include <sprout/algorithm/fixed/set_symmetric_difference.hpp>
 #include <sprout/algorithm/fit/result_of.hpp>
 #include <sprout/sub_array.hpp>
-#include <sprout/detail/overlap_count_2.hpp>
+#include <sprout/detail/set_overlap_count.hpp>
 #include HDR_ALGORITHM_SSCRISK_CEL_OR_SPROUT
 #include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
 
@@ -31,7 +31,7 @@ namespace sprout {
 					offset + NS_SSCRISK_CEL_OR_SPROUT::min(
 						NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)
 							+ NS_SSCRISK_CEL_OR_SPROUT::distance(first2, last2)
-							- 2 * sprout::detail::overlap_count_2(first1, last1, first2, last2, comp)
+							- 2 * sprout::detail::set_overlap_count(first1, last1, first2, last2, comp)
 							,
 						sprout::size(result)
 						)
@@ -71,7 +71,7 @@ namespace sprout {
 					offset + NS_SSCRISK_CEL_OR_SPROUT::min(
 						NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)
 							+ NS_SSCRISK_CEL_OR_SPROUT::distance(first2, last2)
-							- 2 * sprout::detail::overlap_count_2(first1, last1, first2, last2)
+							- 2 * sprout::detail::set_overlap_count(first1, last1, first2, last2)
 							,
 						sprout::size(result)
 						)
diff --git a/sprout/algorithm/fit/set_union.hpp b/sprout/algorithm/fit/set_union.hpp
index ed9f7448..9d85423b 100644
--- a/sprout/algorithm/fit/set_union.hpp
+++ b/sprout/algorithm/fit/set_union.hpp
@@ -7,7 +7,7 @@
 #include <sprout/algorithm/fixed/set_union.hpp>
 #include <sprout/algorithm/fit/result_of.hpp>
 #include <sprout/sub_array.hpp>
-#include <sprout/detail/overlap_count_2.hpp>
+#include <sprout/detail/set_overlap_count.hpp>
 #include HDR_ALGORITHM_SSCRISK_CEL_OR_SPROUT
 #include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
 
@@ -31,7 +31,7 @@ namespace sprout {
 					offset + NS_SSCRISK_CEL_OR_SPROUT::min(
 						NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)
 							+ NS_SSCRISK_CEL_OR_SPROUT::distance(first2, last2)
-							- sprout::detail::overlap_count_2(first1, last1, first2, last2, comp)
+							- sprout::detail::set_overlap_count(first1, last1, first2, last2, comp)
 							,
 						sprout::size(result)
 						)
@@ -71,7 +71,7 @@ namespace sprout {
 					offset + NS_SSCRISK_CEL_OR_SPROUT::min(
 						NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)
 							+ NS_SSCRISK_CEL_OR_SPROUT::distance(first2, last2)
-							- sprout::detail::overlap_count_2(first1, last1, first2, last2)
+							- sprout::detail::set_overlap_count(first1, last1, first2, last2)
 							,
 						sprout::size(result)
 						)
diff --git a/sprout/detail/algorithm_ext.hpp b/sprout/detail/algorithm_ext.hpp
deleted file mode 100644
index 58db22b1..00000000
--- a/sprout/detail/algorithm_ext.hpp
+++ /dev/null
@@ -1,44 +0,0 @@
-#ifndef SPROUT_DETAIL_ALGORITHM_EXT_HPP
-#define SPROUT_DETAIL_ALGORITHM_EXT_HPP
-
-#include <iterator>
-#include <sprout/config.hpp>
-#include <sprout/iterator/operation.hpp>
-
-namespace sprout {
-	namespace detail {
-		//
-		// count_n
-		//
-		template<typename InputIterator, typename Size, typename T>
-		SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type count_n(
-			InputIterator first,
-			Size n,
-			T const& value
-			)
-		{
-			return n == 0
-				? 0
-				: (*first == value ? 1 : 0) + sprout::detail::count_n(sprout::next(first), n - 1, value)
-				;
-		}
-
-		//
-		// count_n_if
-		//
-		template<typename InputIterator, typename Size, typename Predicate>
-		SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type count_n_if(
-			InputIterator first,
-			Size n,
-			Predicate pred
-			)
-		{
-			return n == 0
-				? 0
-				: (pred(*first) ? 1 : 0) + sprout::detail::count_n_if(sprout::next(first), n - 1, pred)
-				;
-		}
-	}	// namespace detail
-}	// namespace sprout
-
-#endif	// #ifndef SPROUT_DETAIL_ALGORITHM_EXT_HPP
diff --git a/sprout/detail/count_n.hpp b/sprout/detail/count_n.hpp
new file mode 100644
index 00000000..224719c6
--- /dev/null
+++ b/sprout/detail/count_n.hpp
@@ -0,0 +1,27 @@
+#ifndef SPROUT_DETAIL_COUNT_N_HPP
+#define SPROUT_DETAIL_COUNT_N_HPP
+
+#include <iterator>
+#include <sprout/config.hpp>
+#include <sprout/iterator/operation.hpp>
+
+namespace sprout {
+	namespace detail {
+		//
+		// count_n
+		//
+		template<typename InputIterator, typename Size, typename T>
+		SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type count_n(
+			InputIterator first,
+			Size n,
+			T const& value
+			)
+		{
+			return n == 0 ? 0
+				: (*first == value ? 1 : 0) + sprout::detail::count_n(sprout::next(first), n - 1, value)
+				;
+		}
+	}	// namespace detail
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_DETAIL_COUNT_N_HPP
diff --git a/sprout/detail/count_n_if.hpp b/sprout/detail/count_n_if.hpp
new file mode 100644
index 00000000..9d117a9c
--- /dev/null
+++ b/sprout/detail/count_n_if.hpp
@@ -0,0 +1,27 @@
+#ifndef SPROUT_DETAIL_COUNT_N_IF_HPP
+#define SPROUT_DETAIL_COUNT_N_IF_HPP
+
+#include <iterator>
+#include <sprout/config.hpp>
+#include <sprout/iterator/operation.hpp>
+
+namespace sprout {
+	namespace detail {
+		//
+		// count_n_if
+		//
+		template<typename InputIterator, typename Size, typename Predicate>
+		SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type count_n_if(
+			InputIterator first,
+			Size n,
+			Predicate pred
+			)
+		{
+			return n == 0 ? 0
+				: (pred(*first) ? 1 : 0) + sprout::detail::count_n_if(sprout::next(first), n - 1, pred)
+				;
+		}
+	}	// namespace detail
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_DETAIL_COUNT_N_IF_HPP
diff --git a/sprout/detail/iterator_ext.hpp b/sprout/detail/iterator_ext.hpp
deleted file mode 100644
index a9a73af7..00000000
--- a/sprout/detail/iterator_ext.hpp
+++ /dev/null
@@ -1,40 +0,0 @@
-#ifndef SPROUT_DETAIL_ITERATOR_EXT_HPP
-#define SPROUT_DETAIL_ITERATOR_EXT_HPP
-
-#include <iterator>
-#include <sprout/config.hpp>
-#include <sprout/iterator/operation.hpp>
-
-namespace sprout {
-	namespace detail {
-		template<typename Iterator>
-		SPROUT_CONSTEXPR typename std::iterator_traits<Iterator>::difference_type bidirectional_distance_impl(
-			Iterator first1,
-			Iterator first2,
-			Iterator last,
-			typename std::iterator_traits<Iterator>::difference_type current = 1
-			)
-		{
-			return first1 == last ? current
-				: first2 == last ? -current
-				: sprout::detail::bidirectional_distance_impl(sprout::next(first1), sprout::prev(first2), last, current + 1)
-				;
-		}
-
-		//
-		// bidirectional_distance
-		//
-		template<typename Iterator>
-		SPROUT_CONSTEXPR typename std::iterator_traits<Iterator>::difference_type bidirectional_distance(
-			Iterator first,
-			Iterator last
-			)
-		{
-			return first == last ? 0
-				: sprout::detail::bidirectional_distance_impl(sprout::next(first), sprout::prev(first), last)
-				;
-		}
-	}	// namespace detail
-}	// namespace sprout
-
-#endif	// #ifndef SPROUT_DETAIL_ITERATOR_EXT_HPP
diff --git a/sprout/detail/overlap_count.hpp b/sprout/detail/overlap_count.hpp
index 581f06f0..d926a632 100644
--- a/sprout/detail/overlap_count.hpp
+++ b/sprout/detail/overlap_count.hpp
@@ -7,12 +7,12 @@
 
 namespace sprout {
 	namespace detail {
-		template<typename Iterator>
-		inline SPROUT_CONSTEXPR typename std::iterator_traits<Iterator>::difference_type overlap_count_impl(
-			Iterator first,
-			Iterator last,
-			typename std::iterator_traits<Iterator>::value_type const& value,
-			typename std::iterator_traits<Iterator>::difference_type current = 0
+		template<typename InputIterator>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type overlap_count_impl(
+			InputIterator first,
+			InputIterator last,
+			typename std::iterator_traits<InputIterator>::value_type const& value,
+			typename std::iterator_traits<InputIterator>::difference_type current = 0
 			)
 		{
 			return first == last
@@ -25,10 +25,10 @@ namespace sprout {
 		//
 		// overlap_count
 		//
-		template<typename Iterator>
-		inline SPROUT_CONSTEXPR typename std::iterator_traits<Iterator>::difference_type overlap_count(
-			Iterator first,
-			Iterator last
+		template<typename InputIterator>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type overlap_count(
+			InputIterator first,
+			InputIterator last
 			)
 		{
 			return first == last
@@ -37,12 +37,12 @@ namespace sprout {
 				;
 		}
 
-		template<typename Iterator, typename Predicate>
-		inline SPROUT_CONSTEXPR typename std::iterator_traits<Iterator>::difference_type overlap_count_impl(
-			Iterator first,
-			Iterator last,
+		template<typename InputIterator, typename Predicate>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type overlap_count_impl(
+			InputIterator first,
+			InputIterator last,
 			Predicate pred,
-			typename std::iterator_traits<Iterator>::value_type const& value
+			typename std::iterator_traits<InputIterator>::value_type const& value
 			)
 		{
 			return first == last
@@ -55,10 +55,10 @@ namespace sprout {
 		//
 		// overlap_count
 		//
-		template<typename Iterator, typename Predicate>
-		inline SPROUT_CONSTEXPR typename std::iterator_traits<Iterator>::difference_type overlap_count(
-			Iterator first,
-			Iterator last,
+		template<typename InputIterator, typename Predicate>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type overlap_count(
+			InputIterator first,
+			InputIterator last,
 			Predicate pred
 			)
 		{
diff --git a/sprout/detail/overlap_count_2.hpp b/sprout/detail/overlap_count_2.hpp
deleted file mode 100644
index 3d855ca6..00000000
--- a/sprout/detail/overlap_count_2.hpp
+++ /dev/null
@@ -1,54 +0,0 @@
-#ifndef SPROUT_DETAIL_OVERLAP_COUNT_2_HPP
-#define SPROUT_DETAIL_OVERLAP_COUNT_2_HPP
-
-#include <iterator>
-#include <sprout/config.hpp>
-#include <sprout/iterator/operation.hpp>
-
-namespace sprout {
-	namespace detail {
-		//
-		// overlap_count_2
-		//
-		template<typename Iterator1, typename Iterator2, typename Compare>
-		inline SPROUT_CONSTEXPR typename std::iterator_traits<Iterator1>::difference_type overlap_count_2(
-			Iterator1 first1,
-			Iterator1 last1,
-			Iterator2 first2,
-			Iterator2 last2,
-			Compare comp
-			)
-		{
-			return first1 != last1 && first2 != last2
-				? comp(*first1, *first2)
-					? sprout::detail::overlap_count_2(sprout::next(first1), last1, first2, last2, comp)
-					: comp(*first2, *first1)
-						? sprout::detail::overlap_count_2(first1, last1, sprout::next(first2), last2, comp)
-						: 1 + sprout::detail::overlap_count_2(sprout::next(first1), last1, sprout::next(first2), last2, comp)
-				: 0
-				;
-		}
-		//
-		// overlap_count_2
-		//
-		template<typename Iterator1, typename Iterator2>
-		inline SPROUT_CONSTEXPR typename std::iterator_traits<Iterator1>::difference_type overlap_count_2(
-			Iterator1 first1,
-			Iterator1 last1,
-			Iterator2 first2,
-			Iterator2 last2
-			)
-		{
-			return first1 != last1 && first2 != last2
-				? *first1 < *first2
-					? sprout::detail::overlap_count_2(sprout::next(first1), last1, first2, last2)
-					: *first2 < *first1
-						? sprout::detail::overlap_count_2(first1, last1, sprout::next(first2), last2)
-						: 1 + sprout::detail::overlap_count_2(sprout::next(first1), last1, sprout::next(first2), last2)
-				: 0
-				;
-		}
-	}	// namespace detail
-}	// namespace sprout
-
-#endif	// #ifndef SPROUT_DETAIL_OVERLAP_COUNT_2_HPP
diff --git a/sprout/detail/set_overlap_count.hpp b/sprout/detail/set_overlap_count.hpp
new file mode 100644
index 00000000..29553809
--- /dev/null
+++ b/sprout/detail/set_overlap_count.hpp
@@ -0,0 +1,54 @@
+#ifndef SPROUT_DETAIL_SET_OVERLAP_COUNT_HPP
+#define SPROUT_DETAIL_SET_OVERLAP_COUNT_HPP
+
+#include <iterator>
+#include <sprout/config.hpp>
+#include <sprout/iterator/operation.hpp>
+
+namespace sprout {
+	namespace detail {
+		//
+		// set_overlap_count
+		//
+		template<typename InputIterator1, typename InputIterator2, typename Compare>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator1>::difference_type set_overlap_count(
+			InputIterator1 first1,
+			InputIterator1 last1,
+			InputIterator2 first2,
+			InputIterator2 last2,
+			Compare comp
+			)
+		{
+			return first1 != last1 && first2 != last2
+				? comp(*first1, *first2)
+					? sprout::detail::set_overlap_count(sprout::next(first1), last1, first2, last2, comp)
+					: comp(*first2, *first1)
+						? sprout::detail::set_overlap_count(first1, last1, sprout::next(first2), last2, comp)
+						: 1 + sprout::detail::set_overlap_count(sprout::next(first1), last1, sprout::next(first2), last2, comp)
+				: 0
+				;
+		}
+		//
+		// set_overlap_count
+		//
+		template<typename InputIterator1, typename InputIterator2>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator1>::difference_type set_overlap_count(
+			InputIterator1 first1,
+			InputIterator1 last1,
+			InputIterator2 first2,
+			InputIterator2 last2
+			)
+		{
+			return first1 != last1 && first2 != last2
+				? *first1 < *first2
+					? sprout::detail::set_overlap_count(sprout::next(first1), last1, first2, last2)
+					: *first2 < *first1
+						? sprout::detail::set_overlap_count(first1, last1, sprout::next(first2), last2)
+						: 1 + sprout::detail::set_overlap_count(sprout::next(first1), last1, sprout::next(first2), last2)
+				: 0
+				;
+		}
+	}	// namespace detail
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_DETAIL_SET_OVERLAP_COUNT_HPP
diff --git a/sprout/math/abs.hpp b/sprout/math/abs.hpp
index 4a96e1e6..af8aee66 100644
--- a/sprout/math/abs.hpp
+++ b/sprout/math/abs.hpp
@@ -4,9 +4,7 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
+#include <sprout/math/detail/config.hpp>
 
 namespace sprout {
 	namespace math {
@@ -27,12 +25,7 @@ namespace sprout {
 		>
 		inline SPROUT_CONSTEXPR FloatType
 		abs(FloatType x) {
-#		if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-			using std::abs;
-#		else
-			using sprout::math::detail::abs;
-#		endif
-			return abs(x);
+			return NS_SPROUT_MATH_DETAIL::abs(x);
 		}
 	}	// namespace math
 
diff --git a/sprout/math/acos.hpp b/sprout/math/acos.hpp
index 92114d25..c0b7d5c4 100644
--- a/sprout/math/acos.hpp
+++ b/sprout/math/acos.hpp
@@ -3,12 +3,10 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/asin.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -32,11 +30,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::acos;
-#	else
-		using sprout::math::detail::acos;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::acos;
 	}	// namespace math
 
 	using sprout::math::acos;
diff --git a/sprout/math/acosh.hpp b/sprout/math/acosh.hpp
index 55eedad9..5f6996a2 100644
--- a/sprout/math/acosh.hpp
+++ b/sprout/math/acosh.hpp
@@ -4,12 +4,10 @@
 #include <limits>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/log.hpp>
 #include <sprout/math/sqrt.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -36,11 +34,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::acosh;
-#	else
-		using sprout::math::detail::acosh;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::acosh;
 	}	// namespace math
 
 	using sprout::math::acosh;
diff --git a/sprout/math/asin.hpp b/sprout/math/asin.hpp
index 15b97f26..7c426ba6 100644
--- a/sprout/math/asin.hpp
+++ b/sprout/math/asin.hpp
@@ -5,13 +5,11 @@
 #include <limits>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/math/factorial.hpp>
 #include <sprout/math/sqrt.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -75,11 +73,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::asin;
-#	else
-		using sprout::math::detail::asin;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::asin;
 	}	// namespace math
 
 	using sprout::math::asin;
diff --git a/sprout/math/asinh.hpp b/sprout/math/asinh.hpp
index 2221c036..e86d1367 100644
--- a/sprout/math/asinh.hpp
+++ b/sprout/math/asinh.hpp
@@ -4,12 +4,10 @@
 #include <limits>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/log.hpp>
 #include <sprout/math/sqrt.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -36,11 +34,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::asinh;
-#	else
-		using sprout::math::detail::asinh;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::asinh;
 	}	// namespace math
 
 	using sprout::math::asinh;
diff --git a/sprout/math/atan.hpp b/sprout/math/atan.hpp
index fd23eb6d..9a5893ad 100644
--- a/sprout/math/atan.hpp
+++ b/sprout/math/atan.hpp
@@ -4,12 +4,10 @@
 #include <cstddef>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/math/factorial.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -70,11 +68,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::atan;
-#	else
-		using sprout::math::detail::atan;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::atan;
 	}	// namespace math
 
 	using sprout::math::atan;
diff --git a/sprout/math/atan2.hpp b/sprout/math/atan2.hpp
index 2b7abea3..7e15766f 100644
--- a/sprout/math/atan2.hpp
+++ b/sprout/math/atan2.hpp
@@ -3,13 +3,11 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/atan.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/math/float_promote.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -40,11 +38,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::atan2;
-#	else
-		using sprout::math::detail::atan2;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::atan2;
 	}	// namespace math
 
 	using sprout::math::atan2;
diff --git a/sprout/math/atanh.hpp b/sprout/math/atanh.hpp
index 88434e4a..28737df9 100644
--- a/sprout/math/atanh.hpp
+++ b/sprout/math/atanh.hpp
@@ -4,11 +4,9 @@
 #include <limits>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/log.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -36,11 +34,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::atanh;
-#	else
-		using sprout::math::detail::atanh;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::atanh;
 	}	// namespace math
 
 	using sprout::math::atanh;
diff --git a/sprout/math/cbrt.hpp b/sprout/math/cbrt.hpp
index 3258d07c..48963c54 100644
--- a/sprout/math/cbrt.hpp
+++ b/sprout/math/cbrt.hpp
@@ -3,12 +3,10 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/pow.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -34,11 +32,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::cbrt;
-#	else
-		using sprout::math::detail::cbrt;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::cbrt;
 	}	// namespace math
 
 	using sprout::math::cbrt;
diff --git a/sprout/math/cos.hpp b/sprout/math/cos.hpp
index de57be78..93579abe 100644
--- a/sprout/math/cos.hpp
+++ b/sprout/math/cos.hpp
@@ -5,11 +5,9 @@
 #include <limits>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/factorial.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -56,11 +54,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::cos;
-#	else
-		using sprout::math::detail::cos;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::cos;
 	}	// namespace math
 
 	using sprout::math::cos;
diff --git a/sprout/math/cosh.hpp b/sprout/math/cosh.hpp
index bd665708..31b31608 100644
--- a/sprout/math/cosh.hpp
+++ b/sprout/math/cosh.hpp
@@ -4,11 +4,9 @@
 #include <cstddef>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/factorial.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -51,11 +49,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::cosh;
-#	else
-		using sprout::math::detail::cosh;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::cosh;
 	}	// namespace math
 
 	using sprout::math::cosh;
diff --git a/sprout/math/detail/config.hpp b/sprout/math/detail/config.hpp
new file mode 100644
index 00000000..7ad9d474
--- /dev/null
+++ b/sprout/math/detail/config.hpp
@@ -0,0 +1,15 @@
+#ifndef SPROUT_MATH_DETAIL_CONFIG_HPP
+#define SPROUT_MATH_DETAIL_CONFIG_HPP
+
+#include <sprout/config.hpp>
+#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+#	include <cmath>
+#endif
+
+#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
+#	define NS_SPROUT_MATH_DETAIL std
+#else	// #ifndef SPROUT_USE_BUILTIN_CMATH_FUNCTION
+#	define NS_SPROUT_MATH_DETAIL sprout::math::detail
+#endif	// #ifndef SPROUT_USE_BUILTIN_CMATH_FUNCTION
+
+#endif	// #ifndef SPROUT_MATH_DETAIL_CONFIG_HPP
diff --git a/sprout/math/exp.hpp b/sprout/math/exp.hpp
index 79d2f623..a529b012 100644
--- a/sprout/math/exp.hpp
+++ b/sprout/math/exp.hpp
@@ -4,11 +4,9 @@
 #include <cstddef>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/factorial.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -51,11 +49,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::exp;
-#	else
-		using sprout::math::detail::exp;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::exp;
 	}	// namespace math
 
 	using sprout::math::exp;
diff --git a/sprout/math/exp2.hpp b/sprout/math/exp2.hpp
index 7d39385f..72fbcd3e 100644
--- a/sprout/math/exp2.hpp
+++ b/sprout/math/exp2.hpp
@@ -3,12 +3,10 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/exp.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -32,11 +30,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::exp2;
-#	else
-		using sprout::math::detail::exp2;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::exp2;
 	}	// namespace math
 
 	using sprout::math::exp2;
diff --git a/sprout/math/expm1.hpp b/sprout/math/expm1.hpp
index 11c5561c..cccbde77 100644
--- a/sprout/math/expm1.hpp
+++ b/sprout/math/expm1.hpp
@@ -3,12 +3,10 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/exp.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -32,11 +30,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::expm1;
-#	else
-		using sprout::math::detail::expm1;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::expm1;
 	}	// namespace math
 
 	using sprout::math::expm1;
diff --git a/sprout/math/fabs.hpp b/sprout/math/fabs.hpp
index 920cc017..b6792cff 100644
--- a/sprout/math/fabs.hpp
+++ b/sprout/math/fabs.hpp
@@ -3,10 +3,8 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -30,11 +28,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::fabs;
-#	else
-		using sprout::math::detail::fabs;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::fabs;
 	}	// namespace math
 
 	using sprout::math::fabs;
diff --git a/sprout/math/fdim.hpp b/sprout/math/fdim.hpp
index f28ecd23..05da8798 100644
--- a/sprout/math/fdim.hpp
+++ b/sprout/math/fdim.hpp
@@ -3,11 +3,9 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/float_promote.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -35,11 +33,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::fdim;
-#	else
-		using sprout::math::detail::fdim;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::fdim;
 	}	// namespace math
 
 	using sprout::math::fdim;
diff --git a/sprout/math/fma.hpp b/sprout/math/fma.hpp
index fe6a2364..53eb990e 100644
--- a/sprout/math/fma.hpp
+++ b/sprout/math/fma.hpp
@@ -3,11 +3,9 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/float_promote.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -42,11 +40,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::fma;
-#	else
-		using sprout::math::detail::fma;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::fma;
 	}	// namespace math
 
 	using sprout::math::fma;
diff --git a/sprout/math/fmax.hpp b/sprout/math/fmax.hpp
index 92baed63..1e3faa5e 100644
--- a/sprout/math/fmax.hpp
+++ b/sprout/math/fmax.hpp
@@ -3,11 +3,9 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/float_promote.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -35,11 +33,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::fmax;
-#	else
-		using sprout::math::detail::fmax;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::fmax;
 	}	// namespace math
 
 	using sprout::math::fmax;
diff --git a/sprout/math/fmin.hpp b/sprout/math/fmin.hpp
index 3b053f52..85f52476 100644
--- a/sprout/math/fmin.hpp
+++ b/sprout/math/fmin.hpp
@@ -3,11 +3,9 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/float_promote.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -35,11 +33,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::fmin;
-#	else
-		using sprout::math::detail::fmin;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::fmin;
 	}	// namespace math
 
 	using sprout::math::fmin;
diff --git a/sprout/math/fpclassify.hpp b/sprout/math/fpclassify.hpp
index 0f073f4f..466897c7 100644
--- a/sprout/math/fpclassify.hpp
+++ b/sprout/math/fpclassify.hpp
@@ -5,6 +5,7 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/isnan.hpp>
 #include <sprout/math/isinf.hpp>
 #include <sprout/math/iszero.hpp>
@@ -28,11 +29,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::fpclassify;
-#	else
-		using sprout::math::detail::fpclassify;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::fpclassify;
 	}	// namespace math
 
 	using sprout::math::fpclassify;
diff --git a/sprout/math/hypot.hpp b/sprout/math/hypot.hpp
index d463484b..0068166f 100644
--- a/sprout/math/hypot.hpp
+++ b/sprout/math/hypot.hpp
@@ -3,12 +3,10 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/float_promote.hpp>
 #include <sprout/math/sqrt.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -36,11 +34,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::hypot;
-#	else
-		using sprout::math::detail::hypot;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::hypot;
 	}	// namespace math
 
 	using sprout::math::hypot;
diff --git a/sprout/math/isfinite.hpp b/sprout/math/isfinite.hpp
index 8eff3f7f..0228ce8e 100644
--- a/sprout/math/isfinite.hpp
+++ b/sprout/math/isfinite.hpp
@@ -4,11 +4,9 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/isnan.hpp>
 #include <sprout/math/isinf.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -25,11 +23,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::isfinite;
-#	else
-		using sprout::math::detail::isfinite;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::isfinite;
 	}	// namespace math
 
 	using sprout::math::isfinite;
diff --git a/sprout/math/isinf.hpp b/sprout/math/isinf.hpp
index ef5daaeb..de6f7d87 100644
--- a/sprout/math/isinf.hpp
+++ b/sprout/math/isinf.hpp
@@ -4,10 +4,8 @@
 #include <limits>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -24,11 +22,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::isinf;
-#	else
-		using sprout::math::detail::isinf;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::isinf;
 	}	// namespace math
 
 	using sprout::math::isinf;
diff --git a/sprout/math/isnan.hpp b/sprout/math/isnan.hpp
index 15fa91e4..892f9f71 100644
--- a/sprout/math/isnan.hpp
+++ b/sprout/math/isnan.hpp
@@ -3,10 +3,8 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -21,11 +19,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::isnan;
-#	else
-		using sprout::math::detail::isnan;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::isnan;
 	}	// namespace math
 
 	using sprout::math::isnan;
diff --git a/sprout/math/isnormal.hpp b/sprout/math/isnormal.hpp
index c00cc755..315674c7 100644
--- a/sprout/math/isnormal.hpp
+++ b/sprout/math/isnormal.hpp
@@ -4,12 +4,10 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/isnan.hpp>
 #include <sprout/math/isinf.hpp>
 #include <sprout/math/issubnormal.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -27,11 +25,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::isnormal;
-#	else
-		using sprout::math::detail::isnormal;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::isnormal;
 	}	// namespace math
 
 	using sprout::math::isnormal;
diff --git a/sprout/math/log.hpp b/sprout/math/log.hpp
index 989b3d4c..2c4ead9c 100644
--- a/sprout/math/log.hpp
+++ b/sprout/math/log.hpp
@@ -5,13 +5,11 @@
 #include <limits>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/math/factorial.hpp>
 #include <sprout/math/sqrt.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -69,11 +67,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::log;
-#	else
-		using sprout::math::detail::log;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::log;
 	}	// namespace math
 
 	using sprout::math::log;
diff --git a/sprout/math/log10.hpp b/sprout/math/log10.hpp
index 8d76c27d..bfb98933 100644
--- a/sprout/math/log10.hpp
+++ b/sprout/math/log10.hpp
@@ -3,12 +3,10 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/log.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -32,11 +30,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::log10;
-#	else
-		using sprout::math::detail::log10;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::log10;
 	}	// namespace math
 
 	using sprout::math::log10;
diff --git a/sprout/math/log1p.hpp b/sprout/math/log1p.hpp
index ee4db6ea..605f6dd9 100644
--- a/sprout/math/log1p.hpp
+++ b/sprout/math/log1p.hpp
@@ -3,11 +3,9 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/log.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -31,11 +29,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::log1p;
-#	else
-		using sprout::math::detail::log1p;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::log1p;
 	}	// namespace math
 
 	using sprout::math::log1p;
diff --git a/sprout/math/log2.hpp b/sprout/math/log2.hpp
index fa38104f..59770748 100644
--- a/sprout/math/log2.hpp
+++ b/sprout/math/log2.hpp
@@ -3,12 +3,10 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/log.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -32,11 +30,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::log2;
-#	else
-		using sprout::math::detail::log2;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::log2;
 	}	// namespace math
 
 	using sprout::math::log2;
diff --git a/sprout/math/pow.hpp b/sprout/math/pow.hpp
index d94bb7fe..1894b323 100644
--- a/sprout/math/pow.hpp
+++ b/sprout/math/pow.hpp
@@ -3,14 +3,12 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/exp.hpp>
 #include <sprout/math/log.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/math/float_promote.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -40,11 +38,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::pow;
-#	else
-		using sprout::math::detail::pow;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::pow;
 	}	// namespace math
 
 	using sprout::math::pow;
diff --git a/sprout/math/signbit.hpp b/sprout/math/signbit.hpp
index ea8e83cf..2aa980fa 100644
--- a/sprout/math/signbit.hpp
+++ b/sprout/math/signbit.hpp
@@ -3,10 +3,8 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -21,11 +19,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::signbit;
-#	else
-		using sprout::math::detail::signbit;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::signbit;
 	}	// namespace math
 
 	using sprout::math::signbit;
diff --git a/sprout/math/sin.hpp b/sprout/math/sin.hpp
index 950c40df..e145807f 100644
--- a/sprout/math/sin.hpp
+++ b/sprout/math/sin.hpp
@@ -3,12 +3,10 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/cos.hpp>
 #include <sprout/math/constants.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -32,11 +30,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::sin;
-#	else
-		using sprout::math::detail::sin;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::sin;
 	}	// namespace math
 
 	using sprout::math::sin;
diff --git a/sprout/math/sinh.hpp b/sprout/math/sinh.hpp
index 25bacda9..4f276584 100644
--- a/sprout/math/sinh.hpp
+++ b/sprout/math/sinh.hpp
@@ -4,11 +4,9 @@
 #include <cstddef>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/factorial.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -51,11 +49,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::sinh;
-#	else
-		using sprout::math::detail::sinh;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::sinh;
 	}	// namespace math
 
 	using sprout::math::sinh;
diff --git a/sprout/math/sqrt.hpp b/sprout/math/sqrt.hpp
index 87181b18..1d67a91e 100644
--- a/sprout/math/sqrt.hpp
+++ b/sprout/math/sqrt.hpp
@@ -4,10 +4,8 @@
 #include <limits>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -59,11 +57,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::sqrt;
-#	else
-		using sprout::math::detail::sqrt;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::sqrt;
 	}	// namespace math
 
 	using sprout::math::sqrt;
diff --git a/sprout/math/tan.hpp b/sprout/math/tan.hpp
index e2a42cfe..198be179 100644
--- a/sprout/math/tan.hpp
+++ b/sprout/math/tan.hpp
@@ -3,12 +3,10 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/sin.hpp>
 #include <sprout/math/cos.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -32,11 +30,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::tan;
-#	else
-		using sprout::math::detail::tan;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::tan;
 	}	// namespace math
 
 	using sprout::math::tan;
diff --git a/sprout/math/tanh.hpp b/sprout/math/tanh.hpp
index 84f393c2..918e7975 100644
--- a/sprout/math/tanh.hpp
+++ b/sprout/math/tanh.hpp
@@ -3,12 +3,10 @@
 
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/math/detail/config.hpp>
 #include <sprout/math/sinh.hpp>
 #include <sprout/math/cosh.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
-#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-#	include <cmath>
-#endif
 
 namespace sprout {
 	namespace math {
@@ -32,11 +30,7 @@ namespace sprout {
 			}
 		}	// namespace detail
 
-#	if SPROUT_USE_BUILTIN_CMATH_FUNCTION
-		using std::tanh;
-#	else
-		using sprout::math::detail::tanh;
-#	endif
+		using NS_SPROUT_MATH_DETAIL::tanh;
 	}	// namespace math
 
 	using sprout::math::tanh;