Wrap Fortran 90/95 in C, Cython and Python
Python Fortran Other
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Fwrap: Wrap Fortran 77/90/95 in C, Cython & Python

Fwrap is a utility that takes Fortran 77/90/95 source code and provides cross-platform & cross-compiler wrappers in C, Cython & Python.

It wraps the basic functionality you'd expect (functions, subroutines, scalar and array arguments for intrinsic types) and will eventually support all features of Fortran 90/95 (derived types, C/Cython/Python callbacks, wrap modules in Python classes).

It is currently under heavy construction and is to be considered beta software until otherwise indicated. All commandline options, APIs etc. are subject to change.


Note: these requirements will loosen as more components are tested; if you would like an earlier version of these requirements tested please email the developers.

Fwrap has been sucessfully tested with:

  • Python 2.5 and 2.6 (2.4 likely coming soon, Py3 support is planned)
  • Cython >= 0.11.1
  • NumPy >= 1.3.0
  • Nose (fairly recent version) for running unittests. The integration tests (see below) do not require nose.
  • A sufficiently modern Fortran 90 compiler.

Fwrap has been tested on three fortran compilers to date (see below), but could benefit from more testing on other compilers/other versions. If you have another version or a different compiler and use fwrap, please let the devs know.

Tested Fortran 90 compilers:

  • gfortran >= 4.4.1 (see note)
  • g95 >= 0.92
  • ifort >= 11.1

Note on gfortran: The gfortran series 4.3.x >= 4.3.3 (widely distributed with many OSes) has a C binding bug that renders the compiler unusable for N-D arrays of type logical or character, where N >= 3. If you can avoid logical and character arrays more than 2 dimensions, then there's no problem. (Gfortran works in 4.4.1 and later.)

Running the Integration Tests

Fwrap has a pretty good testsuite. Getting it running will indicate if everything is working on your system and is highly recommended while Fwrap is in beta stage.

For a failsafe setup, it is necessary to set environment flags to tell Fwrap where to find your system's fortran runtime libraries and executable. For a bash shell, do the following:

$ export F90=/path/to/fortran/executable

$ export LDFLAGS='-L/path/to/fortran/runtime/lib -l<runtimelibname>'

For gfortran:

$ export F90=/usr/local/bin/gfortran

$ export LDFLAGS='-L/usr/local/lib -lgfortran'

Then you can run the tests from the directory containing this README.txt file:

$ python runtests.py -vv --fcompiler=gnu95 --no-cleanup

All the build products will be placed in a directory 'BUILD' which can be safely removed.

If you have success or failure, we'd love to know.

More Information & Resources

See USAGE.txt for basic commandline use.

See the examples directory for some samples to get started.

Project homepage:


Fwrap-users mailing list, for all questions & support:


For fwrap news: