8 files changed, 88 insertions, 51 deletions
diff --git a/Help/guide/tutorial/Step8/CMakeLists.txt b/Help/guide/tutorial/Step8/CMakeLists.txt
index cb87281b9e..97ec6aaa38 100644
--- a/Help/guide/tutorial/Step8/CMakeLists.txt
+++ b/Help/guide/tutorial/Step8/CMakeLists.txt
@@ -16,23 +16,17 @@ target_compile_options(tutorial_compiler_flags INTERFACE
   "$<${msvc_cxx}:$<BUILD_INTERFACE:-W3>>"
 )
 
-
-# should we use our own math functions
-option(USE_MYMATH "Use tutorial provided math implementation" ON)
-
 # configure a header file to pass some of the CMake settings
 # to the source code
 configure_file(TutorialConfig.h.in TutorialConfig.h)
 
 # add the MathFunctions library
-if(USE_MYMATH)
-  add_subdirectory(MathFunctions)
-  list(APPEND EXTRA_LIBS MathFunctions)
-endif()
+add_subdirectory(MathFunctions)
 
 # add the executable
 add_executable(Tutorial tutorial.cxx)
-target_link_libraries(Tutorial PUBLIC ${EXTRA_LIBS} tutorial_compiler_flags)
+
+target_link_libraries(Tutorial PUBLIC MathFunctions tutorial_compiler_flags)
 
 # add the binary tree to the search path for include files
 # so that we will find TutorialConfig.h
diff --git a/Help/guide/tutorial/Step8/MathFunctions/CMakeLists.txt b/Help/guide/tutorial/Step8/MathFunctions/CMakeLists.txt
index f81b563409..872a24a80e 100644
--- a/Help/guide/tutorial/Step8/MathFunctions/CMakeLists.txt
+++ b/Help/guide/tutorial/Step8/MathFunctions/CMakeLists.txt
@@ -1,39 +1,58 @@
-add_library(MathFunctions mysqrt.cxx)
+add_library(MathFunctions MathFunctions.cxx)
+
+# should we use our own math functions
+option(USE_MYMATH "Use tutorial provided math implementation" ON)
+if (USE_MYMATH)
+  target_compile_definitions(MathFunctions PRIVATE "USE_MYMATH")
+
+  # library that just does sqrt
+  add_library(SqrtLibrary STATIC
+              mysqrt.cxx
+              )
+
+  target_link_libraries(SqrtLibrary PUBLIC tutorial_compiler_flags)
+
+  # does this system provide the log and exp functions?
+  include(CheckCXXSourceCompiles)
+  check_cxx_source_compiles("
+    #include <cmath>
+    int main() {
+      std::log(1.0);
+      return 0;
+    }
+  " HAVE_LOG)
+  check_cxx_source_compiles("
+    #include <cmath>
+    int main() {
+      std::exp(1.0);
+      return 0;
+    }
+  " HAVE_EXP)
+
+  # add compile definitions
+  if(HAVE_LOG AND HAVE_EXP)
+    target_compile_definitions(SqrtLibrary
+                               PRIVATE "HAVE_LOG" "HAVE_EXP"
+                               )
+  endif()
+
+  target_link_libraries(MathFunctions PRIVATE SqrtLibrary)
+endif()
 
 # state that anybody linking to us needs to include the current source dir
 # to find MathFunctions.h, while we don't.
 target_include_directories(MathFunctions
-          INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}
-          )
+                           INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}
+                           )
 
 # link our compiler flags interface library
-target_link_libraries(MathFunctions tutorial_compiler_flags)
-
-# does this system provide the log and exp functions?
-include(CheckCXXSourceCompiles)
-check_cxx_source_compiles("
-  #include <cmath>
-  int main() {
-    std::log(1.0);
-    return 0;
-  }
-" HAVE_LOG)
-check_cxx_source_compiles("
-  #include <cmath>
-  int main() {
-    std::exp(1.0);
-    return 0;
-  }
-" HAVE_EXP)
-
-# add compile definitions
-if(HAVE_LOG AND HAVE_EXP)
-  target_compile_definitions(MathFunctions
-                             PRIVATE "HAVE_LOG" "HAVE_EXP")
-endif()
+target_link_libraries(MathFunctions PUBLIC tutorial_compiler_flags)
 
 # install libs
 set(installable_libs MathFunctions tutorial_compiler_flags)
+if(TARGET SqrtLibrary)
+  list(APPEND installable_libs SqrtLibrary)
+endif()
 install(TARGETS ${installable_libs} DESTINATION lib)
 # install include headers
 install(FILES MathFunctions.h DESTINATION include)
diff --git a/Help/guide/tutorial/Step8/MathFunctions/MathFunctions.cxx b/Help/guide/tutorial/Step8/MathFunctions/MathFunctions.cxx
new file mode 100644
index 0000000000..dc28b4b530
--- /dev/null
+++ b/Help/guide/tutorial/Step8/MathFunctions/MathFunctions.cxx
@@ -0,0 +1,19 @@
+#include "MathFunctions.h"
+
+#include <cmath>
+
+#ifdef USE_MYMATH
+#  include "mysqrt.h"
+#endif
+
+namespace mathfunctions {
+double sqrt(double x)
+{
+// which square root function should we use?
+#ifdef USE_MYMATH
+  return detail::mysqrt(x);
+#else
+  return std::sqrt(x);
+#endif
+}
+}
diff --git a/Help/guide/tutorial/Step8/MathFunctions/MathFunctions.h b/Help/guide/tutorial/Step8/MathFunctions/MathFunctions.h
index cd36bccffd..d5c2f224bf 100644
--- a/Help/guide/tutorial/Step8/MathFunctions/MathFunctions.h
+++ b/Help/guide/tutorial/Step8/MathFunctions/MathFunctions.h
@@ -1 +1,5 @@
-double mysqrt(double x);
+#pragma once
+
+namespace mathfunctions {
+double sqrt(double x);
+}
diff --git a/Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx b/Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx
index 7eecd26b5d..28ab042de6 100644
--- a/Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx
+++ b/Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx
@@ -1,8 +1,10 @@
+#include "mysqrt.h"
+
 #include <cmath>
 #include <iostream>
 
-#include "MathFunctions.h"
-
+namespace mathfunctions {
+namespace detail {
 // a hack square root calculation using simple operations
 double mysqrt(double x)
 {
@@ -30,3 +32,5 @@ double mysqrt(double x)
 #endif
   return result;
 }
+}
+}
diff --git a/Help/guide/tutorial/Step8/MathFunctions/mysqrt.h b/Help/guide/tutorial/Step8/MathFunctions/mysqrt.h
new file mode 100644
index 0000000000..593d41e7a6
--- /dev/null
+++ b/Help/guide/tutorial/Step8/MathFunctions/mysqrt.h
@@ -0,0 +1,7 @@
+#pragma once
+
+namespace mathfunctions {
+namespace detail {
+double mysqrt(double x);
+}
+}
diff --git a/Help/guide/tutorial/Step8/TutorialConfig.h.in b/Help/guide/tutorial/Step8/TutorialConfig.h.in
index e23f5213c7..7e4d7fa1fa 100644
--- a/Help/guide/tutorial/Step8/TutorialConfig.h.in
+++ b/Help/guide/tutorial/Step8/TutorialConfig.h.in
@@ -1,4 +1,3 @@
 // the configured options and settings for Tutorial
 #define Tutorial_VERSION_MAJOR @Tutorial_VERSION_MAJOR@
 #define Tutorial_VERSION_MINOR @Tutorial_VERSION_MINOR@
-#cmakedefine USE_MYMATH
diff --git a/Help/guide/tutorial/Step8/tutorial.cxx b/Help/guide/tutorial/Step8/tutorial.cxx
index b3c6a4f43c..a3a2bdce00 100644
--- a/Help/guide/tutorial/Step8/tutorial.cxx
+++ b/Help/guide/tutorial/Step8/tutorial.cxx
@@ -3,13 +3,9 @@
 #include <iostream>
 #include <string>
 
+#include "MathFunctions.h"
 #include "TutorialConfig.h"
 
-// should we include the MathFunctions header?
-#ifdef USE_MYMATH
-#  include "MathFunctions.h"
-#endif
-
 int main(int argc, char* argv[])
 {
   if (argc < 2) {
@@ -23,12 +19,7 @@ int main(int argc, char* argv[])
   // convert input to double
   const double inputValue = std::stod(argv[1]);
 
-  // which square root function should we use?
-#ifdef USE_MYMATH
-  const double outputValue = mysqrt(inputValue);
-#else
-  const double outputValue = sqrt(inputValue);
-#endif
+  const double outputValue = mathfunctions::sqrt(inputValue);
 
   std::cout << "The square root of " << inputValue << " is " << outputValue
             << std::endl;