Optional math static library added.

c/cmake_tutorial/step2/CMakeLists.txt

@@ -0,0 +1,30 @@
+cmake_minimum_required (VERSION 2.6)
+project (Tutorial)
+# The version number.
+set (Tutorial_VERSION_MAJOR 1)
+set (Tutorial_VERSION_MINOR 0)
+
+# configure a header file to pass some of the CMake setting
+# to the source code
+configure_file (
+  "${PROJECT_SOURCE_DIR}/TutorialConfig.h.in"
+  "${PROJECT_BINARY_DIR}/TutorialConfig.h"
+  )
+
+# add the binary tree to the search path for include files
+# so that we will find TutorialConfig.h
+include_directories ("${PROJECT_BINARY_DIR}")
+
+# should we use our own math functions?
+option (USE_MYMATH
+        "Use tutorial provided math implementation" ON)
+
+if (USE_MYMATH)
+  include_directories ("${PROJECT_SOURCE_DIR}/MathFunctions")
+  add_subdirectory (MathFunctions)
+  set (EXTRA_LIBS ${EXTRA_LIBS} MathFunctions)
+endif (USE_MYMATH)
+
+# add the executable
+add_executable (Tutorial tutorial.cxx)
+target_link_libraries (Tutorial ${EXTRA_LIBS})

c/cmake_tutorial/step2/MathFunctions/CMakeLists.txt

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+add_library (MathFunctions mysqrt.cxx)

c/cmake_tutorial/step2/MathFunctions/MathFunctions.h

@@ -0,0 +1 @@
+#include "mysqrt.h"

c/cmake_tutorial/step2/MathFunctions/mysqrt.cxx

@@ -0,0 +1,7 @@
+#include <math.h>
+
+double
+mysqrt (double x)
+{
+  return sqrt (x);
+}

c/cmake_tutorial/step2/MathFunctions/mysqrt.h

@@ -0,0 +1,2 @@
+double
+mysqrt (double);

c/cmake_tutorial/step2/TutorialConfig.h.in

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+// the configured options and settings for Tutorial
+#define Tutorial_VERSION_MAJOR @Tutorial_VERSION_MAJOR@
+#define Tutorial_VERSION_MINOR @Tutorial_VERSION_MINOR@
+#cmakedefine USE_MYMATH

c/cmake_tutorial/step2/tutorial.cxx

@@ -0,0 +1,32 @@
+// A simple program that computes the square root of a number
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include "TutorialConfig.h"
+#ifdef USE_MYMATH
+#include "MathFunctions.h"
+#endif
+
+int main (int argc, char *argv[])
+{
+  if (argc < 2)
+    {
+    fprintf(stdout,"%s Version %d.%d\n",
+            argv[0],
+            Tutorial_VERSION_MAJOR,
+            Tutorial_VERSION_MINOR);
+    fprintf(stdout,"Usage: %s number\n",argv[0]);
+    return 1;
+    }
+  double inputValue = atof(argv[1]);
+#ifdef USE_MYMATH
+  puts ("Using mysqrt ()\n");
+  double outputValue = mysqrt(inputValue);
+#else
+  puts ("Using system sqrt ()\n");
+  double outputValue = sqrt(inputValue);
+#endif
+  fprintf(stdout,"The square root of %g is %g\n",
+          inputValue, outputValue);
+  return 0;
+}