# FileOutputWindow

VTKExamples/Cxx/Utilities/FileOutputWindow

### Description

This example shows how to pipe error output to a text file instead of the usual vtk pop-up window.

### Code

FileOutputWindow.cxx

    #include <vtkFileOutputWindow.h>
    #include <vtkXMLPolyDataReader.h>
    #include <vtkSmartPointer.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkFileOutputWindow> fileOutputWindow =
          vtkSmartPointer<vtkFileOutputWindow>::New();
      fileOutputWindow->SetFileName( "output.txt" );

      // Note that the SetInstance function is a static member of vtkOutputWindow.
      vtkOutputWindow::SetInstance(fileOutputWindow);

      // This causes an error intentionally (file name not specified) - this error will be written to the file output.txt
      vtkSmartPointer<vtkXMLPolyDataReader> reader =
          vtkSmartPointer<vtkXMLPolyDataReader>::New();
      reader->Update();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(FileOutputWindow)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkIOXML QUIET)
    if (NOT VTK_FOUND)
      message("Skipping FileOutputWindow: ${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(FileOutputWindow MACOSX_BUNDLE FileOutputWindow.cxx )
      target_link_libraries(FileOutputWindow PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(FileOutputWindow MACOSX_BUNDLE FileOutputWindow.cxx )
      target_link_libraries(FileOutputWindow PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS FileOutputWindow
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build FileOutputWindow

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

    cd FileOutputWindow/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:

    ./FileOutputWindow

WINDOWS USERS

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