Free-form, fixed-form and file extensions for fortran

http://gcc.gnu.org/wiki/GFortranGettingStarted Free-form, fixed-form and file extensions By default, gfortran is aware of a few file extensions, and its action depends on the extension of the file you ask it to compile. Examples: if the file is named code.f gfortran supposes it is fixed-form source, with no preprocessing needed. if the file is named code.f90 gfortran supposes it is free-form …