.. _FORTRAN:

***************
FORTRAN Wrapper
***************

For FORTRAN, there are two fundamental choices.  Choose one option:

* [Recommended] For FORTRAN 95 and newer, compile a static library of CoolProp and link it with FORTRAN code following the instructions here: :ref:`F95 and newer <FORTRAN95>`
* For FORTRAN 77 and newer, call a shared library of CoolProp using the instructions here: :ref:`F77 and newer <FORTRAN77>`

Common Requirements
===================
Compilation of the Fortran wrapper requires a few :ref:`common wrapper pre-requisites <wrapper_common_prereqs>`

Compilers
=========

On linux, you need gcc and gfortran, which are easy to install using your package manager.

On windows, the most reliable mixed compilation seems to be using the mingw-provided gfortran/gcc combination from mingw-get.  These are the versions used as of June 20, 2014::

    >gfortran --version
    GNU Fortran (GCC) 4.8.1
    Copyright (C) 2013 Free Software Foundation, Inc.

    >gcc --version
    gcc (GCC) 4.8.1
    Copyright (C) 2013 Free Software Foundation, Inc.
    
On OSX, the default compiler that comes with XCode is clang, gcc and g++ at the command prompt are just aliases to clang.  See for instance::

    $ gcc --version
    Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
    Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
    Target: x86_64-apple-darwin13.3.0
    Thread model: posix
    
The most reliable mixed compilation on linux seems to be with the true-gcc/g++ toolchain rather than clang+gfortran.  To install gcc/g++, install gcc/g++ using homebrew with something like::

    brew install gcc-4.9
    
where you can change ``4.9`` to the most up to date version.  Search `braumeister <http://braumeister.org/formula/gcc>`_ for the most recipe for gcc.  Looks like ``gcc`` also works.
    
.. _FORTRAN95:

FORTRAN 95/2003 using ISO_C_BINDING
===================================

Build static library of CoolProp
--------------------------------

On all platforms, start in root folder of recursively-cloned CoolProp repo.

A) On linux,  do::

    mkdir build && cd build
    mkdir gccstatic && cd gccstatic
    cmake ../.. -DCOOLPROP_EXTERNC_STATIC_LIBRARY=ON -DCMAKE_VERBOSE_MAKEFILE=ON
    cmake --build .

B) On Windows, the call to CMake should be done using the MinGW generator, but otherwise the procedure is the same::

    mkdir build && cd build
    mkdir gccstatic && cd gccstatic
    cmake ../.. -G "MinGW Makefiles" -DCOOLPROP_EXTERNC_STATIC_LIBRARY=ON -DCMAKE_VERBOSE_MAKEFILE=ON
    cmake --build .
    
C) On OSX, cmake must use the true, real, gcc/g++ compiler (not clang).  Thus you must so something like this to make sure that it finds the right (true) gcc/g++ (see above)::

    mkdir build && cd build
    mkdir gccstatic && cd gccstatic
    cmake ../.. -DCOOLPROP_EXTERNC_STATIC_LIBRARY=ON -DCMAKE_C_COMPILER="/usr/local/bin/gcc-4.9" -DCMAKE_CXX_COMPILER="/usr/local/bin/g++-4.9" -DCMAKE_VERBOSE_MAKEFILE=ON
    cmake --build .
    
If you are using a different version of gcc, change the version number for g++ and gcc

This will generate the file libCoolProp.a which is a GCC static library that can be linked with GCC/GFORTRAN code.  Copy this .a file into the directory with the coolprop FORTRAN example ``cool_fortran_bind.f90``:

.. code-block:: fortran

    !Example calculates density of saturated liquid propane at 300 K:
    program simple

        USE cpinterface
        
        implicit none

        !Initialize the variables used in the example
        double precision T, Q, dens1
        character(LEN=32) fluid, out1, n1, n2

        T = 300                  ! Temperature [K]
        Q = 0                    ! Quality [-]

        out1 = "D"//CHAR(0)      ! String with of the output Property
        n1  = "T"//CHAR(0)       ! String with of the input Property #1
        n2  = "Q"//CHAR(0)       ! String with of the input Property #2
        fluid    = "Propane"//CHAR(0)   ! String with the fluid name
          
        dens1 = PropsSI(out1, n1, T, n2, Q, fluid)

        Print *, dens1

    end program simple
    
with the interface file ``cpinterface.f90``:

.. code-block:: fortran

    MODULE CPINTERFACE
        INTERFACE
            FUNCTION PropsSI (output, name1, prop1, name2, prop2, fluidname) BIND(C, NAME='PropsSI')
                use iso_c_binding
                real(C_DOUBLE) :: PropsSI
                character(KIND=c_char) :: output(*)
                character(c_char) :: name1(*)
                real(C_DOUBLE), VALUE :: prop1
                character(c_char) :: name2(*)
                real(C_DOUBLE), VALUE :: prop2
                character(kind=c_char) :: fluidname(*)
                    
            END FUNCTION PropsSI
        END INTERFACE
    END MODULE CPINTERFACE

In order to link all the files together, do::

    gfortran -c -Wall cpinterface.f90 cool_fortran_bind.f90
    gcc -o main *.o libCoolProp.a -lstdc++ -ldl -lgfortran
    main
    
On windows, you can leave off the ``-ldl``.

On OSX, you must do the linking stage with true gcc so that it finds the right standard library.  Or alternatively, provide the full path to the libstdc++ static library and link with gfortran with something like::

    gfortran -o main *.o libCoolProp.a /usr/lib/libstdc++.a -ldl

.. warning::

    You MUST(!!!) put the -lstdc++ standard libary *after* libCoolProp.a.  Same thing if you compile the fortran to object file, static library must always be at the end.

.. _FORTRAN77:

FORTRAN77
=========

Pre-Compiled Binaries
---------------------

* Download the appropriate shared library for your architecture from from :sfdownloads:`shared_library`, or the development versions from the buildbot server at :bbbinaries:`shared_library`. Or you can built it yourself given the instructions at :ref:`shared_library`.

Run
---

Use the sample file ``example.for`` given by:

.. code-block:: fortran

    double precision T, Q, D, h, s
    character(LEN=32) Ref,Output, Name1, Name2
    double precision outVal, Prop1, Prop2

    T = 285
    Q = 0
    D = 1250;

    Output = "P"//CHAR(0)
    Name1  = "T"//CHAR(0)
    Prop1  = T
    Name2  = "Q"//CHAR(0)
    Prop2  = Q
    Ref    = "R134a"//CHAR(0)
    outval = 9999999

    write(*,*) "Saturation pressure for R134a: "
    call propssi(Output, Name1, Prop1, Name2, Prop2, Ref, outVal)
    write(*,*) "Result was: ", outVal/1e5, " bar"
    write(*,*) "-----------------------------------------------"
    
    end program

Place the shared library and the sample file in the same directory.  

On linux, build and run the example.for file with::

    gfortran -g -o example example.for -L. -lCoolProp
    LD_LIBRARY_PATH=$PWD:$LD_LIBRARY_PATH example
    
On windows, the current folder is always searched for DLL, so you can just do::

    gfortran -g -o example example.for -L. -lCoolProp
    example
