diff --git a/Bar/CMakeLists.txt b/Bar/CMakeLists.txt
index 791f61e..546eed0 100644
--- a/Bar/CMakeLists.txt
+++ b/Bar/CMakeLists.txt
@@ -13,7 +13,7 @@ set_target_properties(Bar PROPERTIES
   VERSION ${PROJECT_VERSION}
   POSITION_INDEPENDENT_CODE ON
   PUBLIC_HEADER include/bar/Bar.hpp)
-#target_link_libraries(Bar PUBLIC ...)
+target_link_libraries(Bar PRIVATE absl::log)
 add_library(${PROJECT_NAMESPACE}::Bar ALIAS Bar)
 
 add_subdirectory(tests)
diff --git a/Bar/src/Bar.cpp b/Bar/src/Bar.cpp
index 3776b6c..0d2d81d 100644
--- a/Bar/src/Bar.cpp
+++ b/Bar/src/Bar.cpp
@@ -4,167 +4,169 @@
 #include <string>
 #include <utility>
 
+#include "absl/log/log.h"
+
 namespace bar {
 std::vector<std::string> stringVectorOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::string> result(level, std::to_string(level));
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int stringVectorInput(std::vector<std::string> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << item << ", ";
+    LOG(INFO) << item << ", ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int stringVectorRefInput(const std::vector<std::string>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << item << ", ";
+    LOG(INFO) << item << ", ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 std::vector<std::vector<std::string>> stringJaggedArrayOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::vector<std::string>> result;
   result.reserve(level);
   for (int i = 1; i <= level; ++i) {
     result.emplace_back(std::vector<std::string>(i, std::to_string(i)));
   }
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int stringJaggedArrayInput(std::vector<std::vector<std::string>> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << item << ", ";
+      LOG(INFO) << item << ", ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int stringJaggedArrayRefInput(const std::vector<std::vector<std::string>>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << item << ", ";
+      LOG(INFO) << item << ", ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 std::vector<std::pair<int, int>> pairVectorOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::pair<int, int>> result(level, std::make_pair(level, level));
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int pairVectorInput(std::vector<std::pair<int, int>> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << "[" << item.first << "," << item.second << "], ";
+    LOG(INFO) << "[" << item.first << "," << item.second << "], ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int pairVectorRefInput(const std::vector<std::pair<int, int>>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << "[" << item.first << "," << item.second << "], ";
+    LOG(INFO) << "[" << item.first << "," << item.second << "], ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 std::vector<std::vector<std::pair<int, int>>> pairJaggedArrayOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::vector<std::pair<int, int>>> result;
   result.reserve(level);
   for (int i = 1; i <= level; ++i) {
     result.emplace_back(std::vector<std::pair<int, int>>(i, std::make_pair(i, i)));
   }
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int pairJaggedArrayInput(std::vector<std::vector<std::pair<int, int>>> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << "[" << item.first << "," << item.second << "], ";
+      LOG(INFO) << "[" << item.first << "," << item.second << "], ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int pairJaggedArrayRefInput(const std::vector<std::vector<std::pair<int, int>>>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << "[" << item.first << "," << item.second << "], ";
+      LOG(INFO) << "[" << item.first << "," << item.second << "], ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 void freeFunction(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
-  std::cout << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
 }
 
 void freeFunction(int64_t level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
-  std::cout << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
 }
 
 void Bar::staticFunction(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
   freeFunction(level + 1);
-  std::cout << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
 }
 
 void Bar::staticFunction(int64_t level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
   freeFunction(level + 1);
-  std::cout << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
 }
 
 int Bar::getInt() const {
diff --git a/Foo/CMakeLists.txt b/Foo/CMakeLists.txt
index 87defe3..8d6a367 100644
--- a/Foo/CMakeLists.txt
+++ b/Foo/CMakeLists.txt
@@ -12,7 +12,7 @@ set_target_properties(Foo PROPERTIES
   VERSION ${PROJECT_VERSION}
   POSITION_INDEPENDENT_CODE ON
   PUBLIC_HEADER include/foo/Foo.hpp)
-#target_link_libraries(Foo PUBLIC ...)
+target_link_libraries(Foo PRIVATE absl::log)
 add_library(${PROJECT_NAMESPACE}::Foo ALIAS Foo)
 
 add_subdirectory(tests)
diff --git a/Foo/src/Foo.cpp b/Foo/src/Foo.cpp
index 63fff10..e09393b 100644
--- a/Foo/src/Foo.cpp
+++ b/Foo/src/Foo.cpp
@@ -4,167 +4,169 @@
 #include <string>
 #include <utility>
 
+#include <absl/log/log.h>
+
 namespace foo {
 std::vector<std::string> stringVectorOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::string> result(level, std::to_string(level));
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int stringVectorInput(std::vector<std::string> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << item << ", ";
+    LOG(INFO) << item << ", ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int stringVectorRefInput(const std::vector<std::string>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << item << ", ";
+    LOG(INFO) << item << ", ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 std::vector<std::vector<std::string>> stringJaggedArrayOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::vector<std::string>> result;
   result.reserve(level);
   for (int i = 1; i <= level; ++i) {
     result.emplace_back(std::vector<std::string>(i, std::to_string(i)));
   }
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int stringJaggedArrayInput(std::vector<std::vector<std::string>> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << item << ", ";
+      LOG(INFO) << item << ", ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int stringJaggedArrayRefInput(const std::vector<std::vector<std::string>>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << item << ", ";
+      LOG(INFO) << item << ", ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 std::vector<std::pair<int, int>> pairVectorOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::pair<int, int>> result(level, std::make_pair(level, level));
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int pairVectorInput(std::vector<std::pair<int, int>> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << "[" << item.first << "," << item.second << "], ";
+    LOG(INFO) << "[" << item.first << "," << item.second << "], ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int pairVectorRefInput(const std::vector<std::pair<int, int>>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << "[" << item.first << "," << item.second << "], ";
+    LOG(INFO) << "[" << item.first << "," << item.second << "], ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 std::vector<std::vector<std::pair<int, int>>> pairJaggedArrayOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::vector<std::pair<int, int>>> result;
   result.reserve(level);
   for (int i = 1; i <= level; ++i) {
     result.emplace_back(std::vector<std::pair<int, int>>(i, std::make_pair(i, i)));
   }
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int pairJaggedArrayInput(std::vector<std::vector<std::pair<int, int>>> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << "[" << item.first << "," << item.second << "], ";
+      LOG(INFO) << "[" << item.first << "," << item.second << "], ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int pairJaggedArrayRefInput(const std::vector<std::vector<std::pair<int, int>>>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << "[" << item.first << "," << item.second << "], ";
+      LOG(INFO) << "[" << item.first << "," << item.second << "], ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 void freeFunction(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
-  std::cout << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
 }
 
 void freeFunction(int64_t level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
-  std::cout << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
 }
 
 void Foo::staticFunction(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
   freeFunction(level + 1);
-  std::cout << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
 }
 
 void Foo::staticFunction(int64_t level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
   freeFunction(level + 1);
-  std::cout << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
 }
 
 int Foo::getInt() const {
diff --git a/FooBar/CMakeLists.txt b/FooBar/CMakeLists.txt
index 3b09402..20e0443 100644
--- a/FooBar/CMakeLists.txt
+++ b/FooBar/CMakeLists.txt
@@ -1,5 +1,4 @@
 add_library(FooBar OBJECT)
-
 target_sources(FooBar
   PRIVATE
     include/foobar/FooBar.hpp
@@ -7,8 +6,6 @@ target_sources(FooBar
 target_include_directories(FooBar
   PUBLIC
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
-    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../Bar/include>
-    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../Foo/include>
     $<INSTALL_INTERFACE:include>)
 target_compile_features(FooBar PUBLIC cxx_std_20)
 set_target_properties(FooBar PROPERTIES
@@ -16,13 +13,13 @@ set_target_properties(FooBar PROPERTIES
   PUBLIC_HEADER include/foobar/FooBar.hpp)
 # note: macOS is APPLE and also UNIX !
 if(APPLE)
-  set_target_properties(FooBar PROPERTIES
-    INSTALL_RPATH "@loader_path")
+  set_target_properties(FooBar PROPERTIES INSTALL_RPATH "@loader_path")
 elseif(UNIX)
   set_target_properties(FooBar PROPERTIES
     POSITION_INDEPENDENT_CODE ON
     INSTALL_RPATH "$ORIGIN")
 endif()
+target_link_libraries(FooBar PRIVATE absl::log Bar Foo)
 add_library(${PROJECT_NAMESPACE}::FooBar ALIAS FooBar)
 
 add_subdirectory(tests)
diff --git a/FooBar/src/FooBar.cpp b/FooBar/src/FooBar.cpp
index 48028c8..b258aec 100644
--- a/FooBar/src/FooBar.cpp
+++ b/FooBar/src/FooBar.cpp
@@ -5,6 +5,7 @@
 #include <string>
 #include <utility>
 
+#include <absl/log/log.h>
 #include "bar/Bar.hpp"
 #include "foo/Foo.hpp"
 
@@ -12,177 +13,177 @@ namespace foobar {
 using std::make_unique;
 
 std::vector<std::string> stringVectorOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::string> result;
   auto foo_vec = foo::stringVectorOutput(level + 1);
   auto bar_vec = bar::stringVectorOutput(level + 1);
   result.insert(result.end(), foo_vec.begin(), foo_vec.end());
   result.insert(result.end(), bar_vec.begin(), bar_vec.end());
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int stringVectorInput(std::vector<std::string> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << item << ", ";
+    LOG(INFO) << item << ", ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int stringVectorRefInput(const std::vector<std::string>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << item << ", ";
+    LOG(INFO) << item << ", ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 std::vector<std::vector<std::string>> stringJaggedArrayOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::vector<std::string>> result;
   result.reserve(level);
   for (int i = 1; i <= level; ++i) {
     result.emplace_back(std::vector<std::string>(i, std::to_string(i)));
   }
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int stringJaggedArrayInput(std::vector<std::vector<std::string>> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << item << ", ";
+      LOG(INFO) << item << ", ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int stringJaggedArrayRefInput(const std::vector<std::vector<std::string>>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << item << ", ";
+      LOG(INFO) << item << ", ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 std::vector<std::pair<int, int>> pairVectorOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::pair<int, int>> result;
   auto foo_vec = foo::pairVectorOutput(level + 1);
   auto bar_vec = bar::pairVectorOutput(level + 1);
   result.insert(result.end(), foo_vec.begin(), foo_vec.end());
   result.insert(result.end(), bar_vec.begin(), bar_vec.end());
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int pairVectorInput(std::vector<std::pair<int, int>> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << "[" << item.first << "," << item.second << "], ";
+    LOG(INFO) << "[" << item.first << "," << item.second << "], ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int pairVectorRefInput(const std::vector<std::pair<int, int>>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& item : data) {
-    std::cout << "[" << item.first << "," << item.second << "], ";
+    LOG(INFO) << "[" << item.first << "," << item.second << "], ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 std::vector<std::vector<std::pair<int, int>>> pairJaggedArrayOutput(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "()" << std::endl;
   std::vector<std::vector<std::pair<int, int>>> result;
   result.reserve(level);
   for (int i = 1; i <= level; ++i) {
     result.emplace_back(std::vector<std::pair<int, int>>(i, std::make_pair(i, i)));
   }
-  std::cout << "[" << level << "] Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "()" << std::endl;
   return result;
 }
 
 int pairJaggedArrayInput(std::vector<std::vector<std::pair<int, int>>> data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << "[" << item.first << "," << item.second << "], ";
+      LOG(INFO) << "[" << item.first << "," << item.second << "], ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 int pairJaggedArrayRefInput(const std::vector<std::vector<std::pair<int, int>>>& data) {
-  std::cout << "Enter " << __func__ << "()" << std::endl;
-  std::cout << "{";
+  LOG(INFO) << "Enter " << __func__ << "()" << std::endl;
+  LOG(INFO) << "{";
   for (const auto& inner : data) {
-    std::cout << "{";
+    LOG(INFO) << "{";
     for (const auto& item : inner) {
-      std::cout << "[" << item.first << "," << item.second << "], ";
+      LOG(INFO) << "[" << item.first << "," << item.second << "], ";
     }
-    std::cout << "}, ";
+    LOG(INFO) << "}, ";
   }
-  std::cout << "}" << std::endl;
-  std::cout << "Exit " << __func__ << "()" << std::endl;
+  LOG(INFO) << "}" << std::endl;
+  LOG(INFO) << "Exit " << __func__ << "()" << std::endl;
   return data.size();
 }
 
 void freeFunction(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
   foo::freeFunction(level + 1);
   bar::freeFunction(level + 1);
-  std::cout << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
 }
 
 void freeFunction(int64_t level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
   foo::freeFunction(level + 1);
   bar::freeFunction(level + 1);
-  std::cout << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
 }
 
 void FooBar::staticFunction(int level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int)" << std::endl;
   freeFunction(level + 1);
-  std::cout << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int)" << std::endl;
 }
 
 void FooBar::staticFunction(int64_t level) {
-  std::cout << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Enter " << __func__ << "(int64_t)" << std::endl;
   freeFunction(level + 1);
-  std::cout << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
+  LOG(INFO) << "[" << level << "] Exit " << __func__ << "(int64_t)" << std::endl;
 }
 
 FooBar::FooBar() {
diff --git a/FooBarApp/CMakeLists.txt b/FooBarApp/CMakeLists.txt
index 5947ca6..f0f0339 100644
--- a/FooBarApp/CMakeLists.txt
+++ b/FooBarApp/CMakeLists.txt
@@ -1,10 +1,7 @@
 add_executable(FooBarApp)
-target_sources(FooBarApp
-  PRIVATE
-    src/main.cpp)
-target_include_directories(FooBarApp
-  PRIVATE
-    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../FooBar/include>
+target_sources(FooBarApp PRIVATE src/main.cpp)
+target_include_directories(FooBarApp PRIVATE
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
 )
 target_compile_features(FooBarApp PRIVATE cxx_std_20)
 set_target_properties(FooBarApp PROPERTIES
@@ -17,7 +14,14 @@ elseif(UNIX AND NOT APPLE)
   set_target_properties(FooBarApp PROPERTIES
     INSTALL_RPATH "$ORIGIN/../${CMAKE_INSTALL_LIBDIR}")
 endif()
-target_link_libraries(FooBarApp PRIVATE Full)
+target_link_libraries(FooBarApp PRIVATE
+  absl::flags
+  absl::flags_parse
+  absl::log
+  absl::strings
+  protobuf::libprotobuf
+  CMakeCpp::Full
+)
 
 add_executable(${PROJECT_NAMESPACE}::FooBarApp ALIAS FooBarApp)
 
diff --git a/FooBarApp/src/main.cpp b/FooBarApp/src/main.cpp
index c20fe64..a650c4f 100644
--- a/FooBarApp/src/main.cpp
+++ b/FooBarApp/src/main.cpp
@@ -1,34 +1,50 @@
 #include <cstdint>
-#include <foobar/FooBar.hpp>
+#include <fstream>
 #include <iostream>
 #include <string>
+#include <vector>
+
+#include <absl/log/log.h>
+#include <absl/flags/declare.h>
+#include <absl/flags/flag.h>
+#include <absl/flags/parse.h>
+#include <absl/strings/str_join.h>
+#include <foobar/FooBar.hpp>
 
 void* kVar = [] {
   std::cerr << "kFooBarApp\n";
   return nullptr;
 }();
 
-int main(int /*argc*/, char** /*argv*/) {
+int main(int argc, char* argv[]) {
+  absl::ParseCommandLine(argc, argv);
+
+  {
+    const std::vector<std::string> v = {"foo","bar","baz"};
+    std::string s = absl::StrJoin(v, "-");
+    std::cout << "Joined string: " << s << "\n";
+  }
+
   foobar::freeFunction(int{0});
-  std::cout << std::endl;
+  LOG(INFO) << std::endl;
   foobar::freeFunction(int64_t{1});
-  std::cout << std::endl;
+  LOG(INFO) << std::endl;
 
   foobar::FooBar::staticFunction(int{2});
-  std::cout << std::endl;
+  LOG(INFO) << std::endl;
   foobar::FooBar::staticFunction(int64_t{3});
-  std::cout << std::endl;
+  LOG(INFO) << std::endl;
 
   foobar::FooBar f;
   f.setBarInt(13);
   f.setFooInt(17);
-  std::cout << std::to_string(f.getInt()) << std::endl;
+  LOG(INFO) << std::to_string(f.getInt()) << std::endl;
 
   f.setBarInt64(int64_t{31});
   f.setFooInt64(int64_t{42});
-  std::cout << std::to_string(f.getInt64()) << std::endl;
+  LOG(INFO) << std::to_string(f.getInt64()) << std::endl;
 
-  std::cout << f() << std::endl;
+  LOG(INFO) << f() << std::endl;
 
   return 0;
 }