diff --git a/include/doorkeeper/helpers/hashing.hpp b/include/doorkeeper/helpers/hashing.hpp
index dd2dca9..3bd5875 100644
--- a/include/doorkeeper/helpers/hashing.hpp
+++ b/include/doorkeeper/helpers/hashing.hpp
@@ -1,7 +1,23 @@
 #ifndef id4E5F8A0ABA6047BA988D512351B9DD2D
 #define id4E5F8A0ABA6047BA988D512351B9DD2D
 
-//#include "doorkeeper/implem/string_bt.hpp"
+#include "doorkeeper/implem/doorkeeper_conf.h"
+
+#if (defined(__clang__) && \
+		(__clang_major__ == 3 && __clang_minor__ > 5) || (__clang_major__ > 3) \
+	) || (defined(IS_ORIGINAL_GNUC) && \
+		(__GNUC__ == 5 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 5) \
+	)
+#	define IS_PRETTY_FUNC_CONSTEXPR
+#elif defined(__GNUC__)
+//uhm.. nothing :p
+#else
+#	error "Unknown compiler"
+#endif
+
+#if defined(IS_PRETTY_FUNC_CONSTEXPR)
+#	include "doorkeeper/implem/string_bt.hpp"
+#endif
 #include "doorkeeper/implem/compatibility.h"
 #include <cstdint>
 #include <ciso646>
@@ -27,4 +43,8 @@ namespace dk {
 
 #include "doorkeeper/implem/hashing.inl"
 
+#if defined(IS_PRETTY_FUNC_CONSTEXPR)
+#	undef IS_PRETTY_FUNC_CONSTEXPR
+#endif
+
 #endif
diff --git a/include/doorkeeper/implem/hashing.inl b/include/doorkeeper/implem/hashing.inl
index 6389642..62a95c1 100644
--- a/include/doorkeeper/implem/hashing.inl
+++ b/include/doorkeeper/implem/hashing.inl
@@ -1,15 +1,13 @@
 namespace dk {
 	template <typename T, uint32_t D>
 	HashType make_signature_hash() {
-#if defined(__GNUC__)
-		//TODO: use bt::string if possible
+#if IS_PRETTY_FUNC_CONSTEXPR
+		constexpr bt::string<sizeof(__PRETTY_FUNCTION__)-1> func_pretty(__PRETTY_FUNCTION__);
+		return implem::hash_string(func_pretty.data(), func_pretty.size());
+#else
 		const char* const pf = __PRETTY_FUNCTION__;
 		const std::size_t len = sizeof(__PRETTY_FUNCTION__) - 1;
-		//constexpr bt::string<sizeof(__PRETTY_FUNCTION__)-1> func_pretty(pf);
-#else
-#	error "Unknown compiler"
-#endif
-		//return implem::hash_string(func_pretty.data(), func_pretty.size());
 		return implem::hash_string(pf, len);
+#endif
 	}
 } //namespace dk
diff --git a/include/doorkeeper/implem/sequence_bt.hpp b/include/doorkeeper/implem/sequence_bt.hpp
new file mode 100644
index 0000000..131aabc
--- /dev/null
+++ b/include/doorkeeper/implem/sequence_bt.hpp
@@ -0,0 +1,31 @@
+#ifndef id4FAEF395B9ED47CB9D6B50B54C9A289A
+#define id4FAEF395B9ED47CB9D6B50B54C9A289A
+
+#include <cstddef>
+
+namespace dk {
+	namespace bt {
+		template <std::size_t... I>
+		struct index_seq {
+		};
+
+		namespace implem {
+			template <std::size_t MIN, std::size_t MAX, std::size_t... I>
+			struct range_builder;
+
+			template <std::size_t MIN, std::size_t... I>
+			struct range_builder<MIN, MIN, I...> {
+				typedef index_seq<I...> type;
+			};
+
+			template <std::size_t MIN, std::size_t N, std::size_t... I>
+			struct range_builder : public range_builder<MIN, N - 1, N - 1, I...> {
+			};
+		} //namespace implem
+
+		template <std::size_t MIN, std::size_t MAX>
+		using index_range = typename implem::range_builder<MIN, MAX>::type;
+	} //namespace bt
+} //namespace dk
+
+#endif
diff --git a/include/doorkeeper/implem/string_bt.hpp b/include/doorkeeper/implem/string_bt.hpp
new file mode 100644
index 0000000..e92bff5
--- /dev/null
+++ b/include/doorkeeper/implem/string_bt.hpp
@@ -0,0 +1,95 @@
+#ifndef id170B0E6C34D14EBA9B92A35977BDBFB3
+#define id170B0E6C34D14EBA9B92A35977BDBFB3
+
+#include "doorkeeper/implem/sequence_bt.hpp"
+#include <cstddef>
+#include <iostream>
+#include <stdexcept>
+
+namespace dk {
+	namespace bt {
+		template <std::size_t S>
+		class string;
+
+		template <std::size_t S>
+		std::ostream& operator<< ( std::ostream& parStream, const string<S>& parString );
+
+		template <std::size_t S>
+		class string {
+		public:
+			friend std::ostream& operator<< <>( std::ostream& parStream, const string<S>& parString );
+			constexpr string ( const char* parString );
+
+			constexpr std::size_t size ( void ) const { return S - 1; }
+			template <std::size_t S2>
+			constexpr string<S + S2 - 1> operator+ ( const string<S2>& parOther ) const;
+			constexpr char operator[] ( std::size_t parIndex ) const;
+
+			template <typename... Args>
+			constexpr string ( Args... );
+
+			constexpr const char (&data_arr() const)[S] { return m_data; }
+			constexpr const char* data() const { return m_data; }
+
+		private:
+			template <std::size_t... I>
+			constexpr string ( const index_seq<I...>&, const char* parString );
+
+			const char m_data[S];
+		};
+
+		namespace implem {
+			template <std::size_t S, std::size_t S2, std::size_t... I>
+			constexpr string<S + S2 - 1> concat ( const index_seq<I...>&, const string<S>& parLeft, const string<S2>& parRight ) {
+				return string<S + S2 - 1>(
+					(I < S - 1 ? parLeft[I] : (I < S + S2 - 2 ? parRight[I - (S - 1)] : '\0'))...
+				);
+			}
+
+		} //namespace implem
+
+		template <std::size_t S>
+		template <std::size_t... I>
+		constexpr string<S>::string (const index_seq<I...>&, const char* parString) :
+			m_data{parString[I]...}
+		{
+		}
+
+		template <std::size_t S>
+		inline constexpr string<S>::string (const char* parString) :
+			string(index_range<0, S>(), parString)
+		{
+		}
+
+		template <std::size_t S>
+		template <typename... Args>
+		inline constexpr string<S>::string (Args... parArgs) :
+			m_data{parArgs...}
+		{
+		}
+
+		template <std::size_t S>
+		template <std::size_t S2>
+		constexpr inline string<S + S2 - 1> string<S>::operator+ (const string<S2>& parOther) const {
+			return implem::concat(index_range<0, S + S2 - 1>(), string<S>(m_data), parOther);
+		}
+
+		template <std::size_t S>
+		inline std::ostream& operator<< (std::ostream& parStream, const string<S>& parString) {
+			parStream << parString.m_data;
+			return parStream;
+		}
+
+		template <std::size_t S>
+		constexpr char string<S>::operator[] (std::size_t parIndex) const {
+			return (parIndex < S ? m_data[parIndex] : throw std::out_of_range(""));
+		}
+
+		template <std::size_t S>
+		constexpr string<S> make_string (const char (&parData)[S]) {
+			return string<S>(parData);
+		}
+	} //namespace bt
+} //namespace dk
+
+#endif
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 6dd5bb1..173f74d 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,8 +1,15 @@
 cmake_minimum_required(VERSION 2.8 FATAL_ERROR)
 project(doorkeeper CXX C)
 
-include_directories(
-	.
+if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+	set(ID_IS_ORIGINAL_GNUC "1")
+else()
+	set(ID_IS_ORIGINAL_GNUC "0")
+endif()
+
+configure_file(
+	${PROJECT_NAME}_conf.h.in
+	${CMAKE_CURRENT_BINARY_DIR}/include/doorkeeper/implem/${PROJECT_NAME}_conf.h
 )
 
 add_library(${PROJECT_NAME}
@@ -11,3 +18,8 @@ add_library(${PROJECT_NAME}
 	tiger.c
 	hashing.cpp
 )
+
+target_include_directories(${PROJECT_NAME}
+	PRIVATE .
+	PUBLIC ${CMAKE_CURRENT_BINARY_DIR}/include
+)
diff --git a/src/doorkeeper_conf.h.in b/src/doorkeeper_conf.h.in
new file mode 100644
index 0000000..f2bde48
--- /dev/null
+++ b/src/doorkeeper_conf.h.in
@@ -0,0 +1,8 @@
+#ifndef idB523F14441E649E089C21CDE8189640C
+#define idB523F14441E649E089C21CDE8189640C
+
+#if @ID_IS_ORIGINAL_GNUC@ != 0
+#	define IS_ORIGINAL_GNUC
+#endif
+
+#endif