Re: in gfortran, is it faster compile times with *.mod files ?

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

On 11/12/2024 2:59 PM, Thomas Koenig wrote:

Hm... maybe another point. If you want to find discrepancies in
argument lists, you could concatenate all your Fortran source files
into one (which will be large, I presume) and then run "gfortran
-fsyntax-only" on it.  You could then get error messages like
 
$ cat mismatch.f
       subroutine foo(a)
       real a
       end
 
       subroutine bar
       call foo(42)
       end
$ gfortran -fsyntax-only mismatch.f
mismatch.f:6:72:
 
     6 |       call foo(42)
       |                                                                        1
Error: Type mismatch in argument 'a' at (1); passed INTEGER(4) to REAL(4)
 
which you could then investigate.

>
Yeah, I really do not want to do that as it will be only a special run.
I want the errors to show up during each compile so that the programmer
will fix them right then and there.

Then modules are your best choice, I think.

On the other hand, -fsyntax-only is very fast because it does not
do code generation at all.  It might be worth a try to see how
long it takes on your whole codebase, and if it can be integrated
into your normal compilation process.

And we had a user run into an unbalanced argument call to a subroutine
on Monday.  One of us had changed a subroutine argument list and fixed 8
out of the 9 calls.  No telling how many of those land mines are sitting
in our software.

You will find out with -fsyntax-only.  Another possibility is -flto, but
then the final "linking" step will take a very long time.  Might speed
up things in the resulting executable, though.