************************************************************************
* Build and Test HDF4 Examples with CMake                              *
************************************************************************

Notes: This short instruction is written for users who want to quickly build
       HDF4 Examples using the HDF4 binary package using the CMake tools.

       More information about using CMake can be found at the Kitware
       site, www.cmake.org.

       CMake uses the command line; however, the visual CMake tool is
       available for the configuration step. The steps are similar for
       all of the operating systems supported by CMake.

       NOTES:
         1. Using CMake for building and using HDF4 is under active
            development. While we have attempted to provide error-free
            files, please understand that development with CMake has not
            been extensively tested outside of HDF. The CMake specific
            files may change before the next release.

         2. CMake for HDF4 development should be usable on any system
            where CMake is supported. Please send us any comments on how
            CMake support can be improved on any system.


========================================================================
I. Preconditions
========================================================================

   1. We suggest you obtain the latest CMake from the Kitware
      web site. The HDF 4.3.x product requires a minimum CMake version
      of 3.18. If you are using VS2022, the minimum CMake version is 3.21.
      CMakePresets.json, requires CMake 3.25 or higher.

   2. You have installed the HDF4 library built with CMake, by executing
      the HDF Install Utility (the *.msi file in the binary package for
      Windows or the *.sh on Linux). If you are using a Windows platform,
      you can obtain a pre-built binary from The HDF Group's website
      at www.hdfgroup.org.

   3. Set the HDF4_ROOT CMake variable, -DHDF4_ROOT=<install_path>
      or environment variable, set(ENV{HDF4_ROOT} "<install_path>")
      to the installed location of HDF4.
         On Windows:
            HDF4_ROOT=C:/Program Files/HDF_Group/HDF4/z.y.x/
         On unix:
            HDF4_ROOT=<install root folder>/HDF_Group/HDF4/z.y.x/

      If you are using shared libraries, you may need to add to the path
      environment variable. Set the path environment variable to the
      installed location of the library files for HDF4.
         On Windows (*.dll):
            PATH=%PATH%;C:/Program Files/HDF_Group/HDF4/z.y.x/bin
         On unix (*.so):
            LD_LIBRARY_PATH=$LD_LIBRARY_PATH:<install root folder>/HDF_Group/HDF4/z.y.x/lib

      (Note there are no quote characters used on Windows and all platforms
      use forward slashes)

   4. Create separate source and build directories.
      (CMake commands are executed in the build directory)



========================================================================
II. Building HDF4 Examples with CMake
========================================================================

Go through these steps to build HDF4 applications with CMake.

   1. Run CMake
   2. Configure the cache settings
   3. Build HDF4 Examples
   4. Test HDF4 Examples.

These steps are described in more detail below.



   1. Run CMake

      The visual CMake executable is named "cmake-gui.exe" on Windows and should be
      available in your Start menu. For Linux, UNIX, and Mac users the
      executable is named "cmake-gui" and can be found where CMake was
      installed.

      Specify the source and build directories. Make the build and source
      directories different. For example on Windows, if the source is at
      c:\MyHDFstuff\HDF4Examples, then use c:\MyHDFstuff\HDF4Examples\build or
      c:\MyHDFstuff\build\HDF4Examples for the build directory.

      PREFERRED:
        Users can perform the configuration step without using the visual
        cmake-gui program. The following is an example command line
        configuration step executed within the build directory:

        cmake -G "<generator>"  [-D<options>]  <sourcepath>

        Where <generator> is
            * Borland Makefiles
            * MSYS Makefiles
            * MinGW Makefiles
            * NMake Makefiles
            * Unix Makefiles
            * Visual Studio 15 2017
            * Visual Studio 15 2017 Win64
            * Visual Studio 16 2019
            * ... in addition VS2019 will need to set the "-A" option,
            * ... [Win32, x64, ARM, ARM64]
            * Visual Studio 17 2022
            * ... in addition VS2022 will need to set the "-A" option,
            * ... [Win32, x64, ARM, ARM64]

        <options> is:
            * H4EX_BUILD_TESTING:BOOL=ON
            * BUILD_SHARED_LIBS:BOOL=[ON | OFF]
            * H4EX_BUILD_FORTRAN:BOOL=[ON | OFF]
            * H4EX_BUILD_JAVA:BOOL=[ON | OFF]

        if the hdf4 library was built with a namespace (i.e. "hdf4::") add:
            -D HDF4_NAMESPACE:STRING=hdf4::

   2. Configure the cache settings

      2.1  Visual CMake users, click the Configure button. If this is the first time you are
           running cmake-gui in this directory, you will be prompted for the
           generator you wish to use (for example on Windows, Visual Studio 15).
           CMake will read in the CMakeLists.txt files from the source directory and
           display options for the HDF4 Examples project. After the first configure you
           can adjust the cache settings and/or specify locations of other programs.

           Any conflicts or new values will be highlighted by the configure
           process in red. Once you are happy with all the settings and there are no
           more values in red, click the Generate button to produce the appropriate
           build files.

           On Windows, if you are using a Visual Studio generator, the solution and
           project files will be created in the build folder.

           On linux, if you are using the Unix Makefiles generator, the Makefiles will
           be created in the build folder.

      2.2  Alternative command line example on Windows in c:\MyHDFstuff\HDF4Examples\build directory:

           cmake -G "Visual Studio 19" -DH4EX_BUILD_TESTING:BOOL=ON -DBUILD_SHARED_LIBS:BOOL=ON ..

   3. Build HDF4 examples

      On Windows, you can build HDF4 examples using either the Visual Studio Environment
      or the command line. The command line is normally used on linux, Unix, and Mac.

      To build from the command line, navigate to your build directory and
      execute the following:

              cmake --build . --config {Debug | Release}

      NOTE: "--config {Debug | Release}" may be optional on your platform. We
            recommend choosing either Debug or Release on Windows. If you are
            using the pre-built binaries from HDF, use Release.

      3.1  If you wish to use the Visual Studio environment, open the solution
           file in your build directory. Be sure to select either Debug or
           Release and build the solution.

   4. Test HDF4 Examples.

      To test the build, navigate to your build directory and execute:

              ctest . -C {Debug | Release}

      NOTE: "-C {Debug | Release}" may be optional on your platform. We
            recommend choosing either Debug or Release to match the build
            step on Windows.

   5. The files that support building with CMake are all of the files in the
      config/cmake folder, the CMakeLists.txt files in each source folder, and
      CTestConfig.cmake. CTestConfig.cmake is specific to the internal testing
      performed by The HDF Group. It should be altered for the user's
      installation and needs. The cacheinit.cmake file settings are used by
      The HDF Group for daily testing. It should be altered/ignored for the user's
      installation and needs.



========================================================================
III. Using HDF4 Libraries with Visual Studio 2008 (no longer supported)
========================================================================

   1. Set up path for external libraries and headers

      Invoke Microsoft Visual Studio and go to "Tools" and select "Options",
      find "Projects", and then "VC++ Directories".

      1.1 If you are building on 64-bit Windows, find the "Platform" dropdown
          and select "x64".

      1.2 Find the box "Show directories for", choose "Include files", add the
          header path (i.e. c:\Program Files\HDF Group\HDF4\hdf4.3.x\include)
          to the included directories.

      1.3 Find the box "Show directories for", choose "Library files", add the
          library path (i.e. c:\Program Files\HDF Group\HDF4\hdf4.3.x\lib)
          to the library directories.

      1.4 If using Fortran libraries, you will also need to setup the path
          for the Intel Fortran compiler.


************************************************************************

Need further assistance, send email to help@hdfgroup.org

