Tutorial: Improve Step 5

* Updated output message
* Use 'target_compile_definitions' for HAVE_LOG and HAVE_EXP

Previously, the change from using TutorialConfig.h to
target_compile_definitions happened without explanation as part of Step 8.

2 files changed, 8 insertions, 2 deletions

diff --git a/Help/guide/tutorial/Step9/MathFunctions/CMakeLists.txt b/Help/guide/tutorial/Step9/MathFunctions/CMakeLists.txt
index c8cd1dd..b4d337b 100644
--- a/Help/guide/tutorial/Step9/MathFunctions/CMakeLists.txt
+++ b/Help/guide/tutorial/Step9/MathFunctions/CMakeLists.txt
@@ -26,6 +26,12 @@ target_include_directories(MathFunctions
 # and that anything that links to use will get this define
 target_compile_definitions(MathFunctions INTERFACE "USE_MYMATH")
 
+# does this system provide the log and exp functions?
+include(CheckSymbolExists)
+set(CMAKE_REQUIRED_LIBRARIES "m")
+check_symbol_exists(log "math.h" HAVE_LOG)
+check_symbol_exists(exp "math.h" HAVE_EXP)
+
 if(HAVE_LOG AND HAVE_EXP)
   target_compile_definitions(MathFunctions
                              PRIVATE "HAVE_LOG" "HAVE_EXP")
diff --git a/Help/guide/tutorial/Step9/MathFunctions/mysqrt.cxx b/Help/guide/tutorial/Step9/MathFunctions/mysqrt.cxx
index 8b82141..2b1d889 100644
--- a/Help/guide/tutorial/Step9/MathFunctions/mysqrt.cxx
+++ b/Help/guide/tutorial/Step9/MathFunctions/mysqrt.cxx
@@ -16,8 +16,8 @@ double mysqrt(double x)
   // if we have both log and exp then use them
 #if defined(HAVE_LOG) && defined(HAVE_EXP)
   double result = exp(log(x) * 0.5);
-  std::cout << "Computing sqrt of " << x << " to be " << result << " using log"
-            << std::endl;
+  std::cout << "Computing sqrt of " << x << " to be " << result
+            << " using log and exp" << std::endl;
 #else
   // use the table to help find an initial value
   double result = x;