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# FloatingPointExceptions

VTKEx/Cxx/SimpleOperations/FloatingPointExceptions

### Description

This example makes the illegal division by zero produce an error: Error: Floating point exception detected. Signal 8 rather than simply store "inf" in y.

Question

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### Code

FloatingPointExceptions.cxx

    #include <vtkFloatingPointExceptions.h>

    // Avoid the "potential divide by 0" warning from the Microsoft
    // compiler, since this example intentionally divides by 0
    #ifdef _MSC_VER
    #pragma warning (disable: 4723)
    #endif

    int main(int, char *[])
    {
      // Disabled by default with gcc or visual studio.
      // Enabled by default by Borland CC.
      vtkFloatingPointExceptions::Enable();

      double x = 0.0;
      double y = 1.0/x; // floating-point exception

      std::cout << "x: " << x << " y: " << y << std::endl;

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(FloatingPointExceptions)

    find_package(VTK COMPONENTS
      vtkCommonCore QUIET)
    if (NOT VTK_FOUND)
      message("Skipping FloatingPointExceptions: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(FloatingPointExceptions MACOSX_BUNDLE FloatingPointExceptions.cxx )
      target_link_libraries(FloatingPointExceptions PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(FloatingPointExceptions MACOSX_BUNDLE FloatingPointExceptions.cxx )
      target_link_libraries(FloatingPointExceptions PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS FloatingPointExceptions
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build FloatingPointExceptions

Click here to download FloatingPointExceptions and its CMakeLists.txt file. Once the tarball FloatingPointExceptions.tar has been downloaded and extracted,

    cd FloatingPointExceptions/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./FloatingPointExceptions

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.