Why does gfortran treat files with different suffix differently?

[Steve Kargl]

On Thu, May 09, 2013 at 10:51:33AM -0500, Peng Yu wrote:
> Hi,
> 
> The following shows that gfortran treat .f and .f90 files differently.
> But I don't find this documented in the man page. Could anybody let me
> know where this is documented? Thanks.
> 

See section 1.2 in the gfortran manual for detailed answer.

Short answer.  .f is assumed to be a fixed form source code
and .f90 is assumed to be free form source code.

-- 
Steve