Building
========

Prerequisites:

* CMake version 3.1 or newer.

* YAJL 2.0.1 or newer. You need both the library and the header files.
  This is a standard binary package in most any Linux distribution. Note
  that the header files are often in a separate "devel" package. The source
  can be downloaded from https://github.com/lloyd/yajl/releases if you must
  build the library yourself.

* A Fortran compiler that supports the 2003/2008 features used by YAJL-Fort,
  and its companion (or a compatible) C compiler.

Clone the YAJL-Fort source repository with SSH::

  git clone git@github.com:nncarlson/yajl-fort.git

or with HTTPS::

  git clone https://github.com/nncarlson/yajl-fort.git

Set your ``FC`` and ``CC`` environment variables to your Fortran and C
compilers. If YAJL is not in a standard location you will also need to
set your ``YAJL_ROOT`` environment variable to the root directory of the
YAJL installation. Then create a build directory and run ``cmake`` from
the directory::

  cd yajl-fort
  mkdir build
  cd build
  cmake ..

CMake should find your compilers with the help of the ``FC`` and ``CC``
variables. The default is to configure a ``Release`` build. Some CMake
variables you might want to set on the ``cmake`` command line:

* ``CMAKE_BUILD_TYPE``: to specify a ``Debug`` build type, for example
* ``CMAKE_Fortran_FLAGS``: additional Fortran compiler flags
* ``CMAKE_INSTALL_PREFIX``: where to install the library and module files

Then compile the library and tests, and run the tests (all should pass)::

  make
  ctest

Then see the documentation for the :ref:`yajl_fort <yajl_fort>` and
:ref:`json <json-module>` modules and the examples therein.

Compiler status and notes
-------------------------
The following compilers are known to work:

* NAG 5.3.2, 6.0, 6.1, and 6.2
* Intel 16.0.2, 17.0.6, 18.0.1
* GFortran 6.4.1, 7.2.1, 7.3.1, 8.1, 8.2
* IBM xlf 15.1.6, 16.1.0 (must use the xlf2008 executable)

The following compilers **appear** to work now. All tests are passing but
the interface has not been extensively exercised in actual applications.

* Flang March 2019 Binary Release (but no earlier)
* PGI 19.4 (but no earlier)

The ``CMakeLists.txt`` file has special stanzas for some compilers that set
compiler flags and preprocessor macros that are known to be needed. If you
are using another compiler it too may need specific compiler flags or macros
defined.  These can be set on the ``cmake`` command line with
``CMAKE_Fortran_FLAGS`` or a stanza can be added to the ``CMakeLists.txt``
file.