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Installation Instructions


In order to build the Nexus C API the following software has to be installed on the build system

  • C compiler
  • CMake >= 2.8.8
  • HDF5 libraries and header files
  • Optional: HDF4 libraries and header files
  • Optional: MXML libraries and header files
  • doxygen: for building the API documentation
  • rst2man: for building manpages

Building the code on Linux

Enabling a physical file formats

By default the NAPI is only built with HDF5 support. You can explicit switch on a particular file format by defining the appropriate CMake variable during configuration

  • -DENABLE_HDF5=1 for HDF5
  • -DENABLE_HDF4=1 for HDF4
  • and -DENABLE_MXML=1 for MXML

CMake tries then to figure out the locations of the required library binaries and header files. This should work if the library provides a pkg-config file and/or is installed in one of the systems default locations.

If your library is not in a default location you have basically two options.

  1. if the library is installed with a pkg-config file you can add the path to this file to your PKG_CONFIG_PATH environment variable.
  2. define CMake variables during configuration that point to the appropriate location.

For the second option the following CMake variables are available

Enable language bindings

The library provides bindings for C++, Fortran 77, and Fortran 90. To enable them set the following variables to one during code configuration

CMAKE variable language bindings
ENABLE_CXX build with C++ bindings
ENABLE_FORTRAN77 build with Fortran 77 bindings
ENABLE_FORTRAN90 build with Fortran 90 bindings

Enable applications

Aside with the C-library the NAPI source distribution ships a couple of command line programs to work with NeXus files. These programs are not built by default. In order to include them in the build the ENABLE_APPS variable must be set to ON.

Program Description
nxbrowse browse a NeXus file
nxdir list the contents of a NeXus file
nxconvert convert a NeXus file to whatever?
nxtraverse list the contents of a NeXus file

Building the distribution with these utility applications pulls in some additional build requirements. These are

  • libreadline
  • libtermcap
  • libhistory (most probably provided by the libreadline package)
  • libxml2

As one cannot select an individual program to be included in the build, all these build dependencies must be satisified when ENABLE_APPS is set to ON in order for the build to succeed.

Running the build

To build the library and program binaries simply use

$ mkdir build
$ cd build
$ cmake -DENABLE_APPS=ON .. # building with tools as example config option
$ make

from the source directoy. For installation run

$ make install

This procedure installs the binaries, header files, and the man pages for the programs (if configured to build them). To build the API documentation use

$ make html
$ make install-html

Building the code on Windows

These instructions will build everything except the applications using LIBXML2 (e.g. nxtranslate)

  • Download and install Win32/x64 HDF4 and/or HDF5 libraries from HDF web site
    • within these installations is a "cmake" directory, I needed to remove/rename this to get everything to configure properly
  • Download MXML source from
    • open the vcnet directory
    • you need to edit mxml1.def and a add a single line containing the text mxml_error to the end of this file
    • open the visual studio solution, chose either Win32 or x64 build type as appropriate, and build the project
    • copy the files mxml.h mxml1.lib mxml1.dll to some other location
  • Define HDF4_ROOT, HDF5_ROOT and MXML_ROOT Windows environment variables to point to the top of each installed area
    • you should use / rather than \ for the paths specified in these variables
  • Create an empty build directory somewhere - this can be within your nexus source tree
  • Run CMAKE-GUI to generate Visual studio solutions files
    • Provide source and build paths in the relevant boxes
    • Click on Configure, choose appropriate visual studio version (with Win64 suffix if needed) when prompted
    • A list of options will appear, select the ENABLE_* boxes for the components you need
    • Also check the CMAKE_INSTALL_PREFIX is appropriate, this is the root where file may be installed to later
    • press Configure again
    • If anything now appears in red, it means it is a newly displayed option. If you change ones of these (or any other value) you need to pres Configure again, otherwise move onto the next step
    • Click on Generate
  • Browse to the build directory and open the generated NeXus.sln
  • Build the solution
    • If you wish to copy files to the install directory specified above, right click and Build the INSTALL project
    • If you wish to run the tests, right click and Build the RUN_TESTS project. Currently tests pick up the DLL installed above, this will be fixed later to point to the DLL in the build tree.