GNU Fortran or GFortran is the GNU Fortran compiler, which is part of the GNU Compiler Collection (GCC). As of July 2020, GFortran was almost fully implementing Fortran 2008 and about 20% of Fortran 2018. It supports the OpenMP multi-platform shared memory multiprocessing, up to its latest version (4.5). GFortran is also compatible with most language extensions and compilation options supported by g77, and many other popular extensions of the Fortran language. Since GCC version 4.0.0, released in April 2005, GFortran has replaced the older g77 compiler. The new Fortran front-end for GCC was rewritten from scratch, after the principal author and maintainer of g77, Craig Burley, decided in 2001 to stop working on the g77 front end. GFortran forked off from g95 in January 2003, which itself started in early 2000. The two codebases have "significantly diverged" according to GCC developers, and g95 is not maintained anymore since 2013. Since 2010 the front-end, like the rest of the GCC project, has been migrated to C++, where it was previously written in C. Development of the compiler by volunteer users continues and each new version of GCC incorporates better support for the latest language standards and bug fixes. See also GNU Compiler Collection Cray pointer Quadruple precision scientific notation References External links GFortran on the GCC Wiki OpenMP in gfortran information web page Fortran compilers Free compilers and interpreters Fortran