Fortran Extensions

[JohnNichols]

So for many years I used just .for, and then I got used to .f90.   Why does the .f extension default to .for and what other extensions are actually supported by Intel Fortran?  

I read Arjun's article on this matter, so I understand, but who decides this? 

Just curious. 

[Steve_Lionel]

Doctor Fortran in "Source Form Just Wants to be Free" - Doctor Fortran (stevelionel.com)

The Intel documentation lists the supported file types. .for was DEC's preferred type, .f was popular in the UNIX/Linux world - Intel Fortran supports both of those for fixed-form source. For free-form source, only .f90 is supported. (You can see my view on this in the post linked above.)

I have seen some argue that .f should be "reclaimed" for free-form source, but that would be disastrous for zillions of existing builds. I'd be happier to see a new file type, such as .ffr, be adopted for free-form, but I doubt that's going to happen.

[JohnNichols]

Thanks, so using a .f is ok.  

[Steve_Lionel]

.ftn is also accepted as fixed-form. For more details, see Understanding File Extensions (intel.com)