A Fortran 2008 JSON API
Fortran CMake Perl Shell C++
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GitHub release A Fortran 2008 JSON API

Table of Contents


Build Status Codecov

GitHub issues Blocked by Vendor Bug Ready in backlog In Progress Needs Review

Take a look at the CHANGELOG for a list of changes since the latest release.


Brief description

A user-friendly, thread-safe, and object-oriented API for reading and writing JSON files, written in modern Fortran.



GitHub release homebrew version

Download the official versioned releases here. Or, get the latest development code from the master branch here.

NEWS: As of June 7, 2015, json-fortran can be downloaded and installed with the homebrew package manager on Mac OS X. Once homebrew is installed, make sure that the formulae are up to date, view the package options and caveats, and install the json-fortran formula:

brew update
brew info json-fortran
brew install --with-unicode-support json-fortran

Please note, if you wish to support usage of JSON-Fortran with multiple Fortran compilers, please follow the CMake installation instructions below, as the homebrew installation is only intended to support a single Fortran compiler. Cheers!


Building the library

The code requires a Fortran compiler that supports various Fortran 2003 and Fortran 2008 features such as: allocatable strings, newunit, generic, class, and abstract interface. It has been successfully compiled with the Intel Fortran compiler 13.1.0 (and greater) and the GNU gfortran compiler [4.9 and greater]. It has also been reported that the library can be built (using the CMake build script) with the NAG Fortran compiler 6.0

Currently, several ways are provided to build the JSON-fortran library (libjsonfortran).

  • A build script, build.sh is provided in the project root directory. This script uses FoBiS to build the JSON-Fortran library and the unit tests. Edit the script to use either the Intel Fortran Compiler or Gfortran. Note that version 1.2.5 of FoBiS (or later) is required.

  • A Visual Studio project is included for building the library (and unit tests) on Windows with the Intel Fortran Compiler. The project has been tested with Visual Studio 2010 and 2013.

  • A CMake build system is provided. This build system has been tested on Mac and Linux using the Intel Fortran Compiler, gfortran 4.9, and NAG Fortran 6.0. It has not been tested on Windows. This CMake based build provides an install target, and exports from both the install location and the build location so that building and using JSON-Fortran in another CMake based project is trivial. To get started with the CMake based build, set the environment variable FC to point to your Fortran compiler, and create a build directory. Then (cmake-gui|ccmake|cmake) /path/to/json-fortran-root to configure, make to build and make install to optionally install. As long as the project is built with CMake, other CMake projects can find it and link against it. For example, if you have a second copy of the JSON-Fortran project tree, and want to build the unit tests linking against those compiled/installed by the first copy:

cmake_minimum_required ( VERSION 2.8.8 FATAL_ERROR )
enable_language ( Fortran )
project ( jf_test NONE )

find_package ( jsonfortran-${CMAKE_Fortran_COMPILER_ID} 5.1.0 REQUIRED )
include_directories ( "${jsonfortran_INCLUDE_DIRS}" )

file ( GLOB JF_TEST_SRCS "src/tests/jf_test_*.f90" )
foreach ( UNIT_TEST ${JF_TEST_SRCS} )
  get_filename_component ( TEST ${UNIT_TEST} NAME_WE )
  add_executable ( ${TEST} ${UNIT_TEST} )
  target_link_libraries ( ${TEST} jsonfortran-static )
  # or for linking against the dynamic/shared library:
  # target_link_libraries ( ${TEST} jsonfortran ) # instead



The API documentation for the latest release version can be found here. The documentation can also be generated by processing the source files with FORD. Note that both the shell script and CMake will also generate these files automatically in the documentation folder, assuming you have FORD installed.

Some examples can also be found on the wiki.



Ready in backlog

Want to help? Take a quick look at our contributing guidelines then claim something in the "ready" column on our Waffle.io and Fork. Commit. Pull request.



The JSON-Fortran source code and related files and documentation are distributed under a permissive free software license (BSD-style). See the LICENSE file for more details.