Topic: Modules in SF

I am a beginner in Fortran, and maybe I am just stupid, but I have spent a huge amount of time trying to write programs that use modules that I have done myself. I need to make several numerical calculation programs, and some tasks are similar in all these programs. Therefore it would be nice to make a module that contains many functions that I need often. Can anyone tell me what goes wrong in the very simple test program below:

I have made a simple  project with the name moduletest. It contains two files:

moduletest_main.f90:

program moduletest
use testmodule
implicit none
real :: x, y
x=2.0
y=testmodulefunction(x)
write(*,*) x, y
end program moduletest

testmodule.mod:

module testmodule
implicit none
real :: x, y
contains
function testmodulefunction(x) result(y)
y=x**2
end function testmodulefunction
end module testmodule


Build => Build Now! (F6) produces the following log:

==============================================================================
Open Watcom Make Version 1.9 (Built on May 17 2012)
Portions Copyright (c) 1988-2002 Sybase, Inc. All Rights Reserved.
Source code is available under the Sybase Open Watcom Public License.
See http://www.openwatcom.org/ for details.
    "C:\Program Files (x86)\Simply Fortran\mingw-w64\bin\gfortran.exe" -c -o build\moduletest_main.o -g -m32   -Jmodules .\moduletest_main.f90
.\moduletest_main.f90:2.4:

use testmodule
    1
Fatal Error: File 'testmodule.mod' opened at (1) is not a GFORTRAN module file
Error(E42): Last command making (build\moduletest_main.o) returned a bad status
Error(E02): Make execution terminated

* Complete *

  • jeff
  • Administrator
  • Offline

Re: Modules in SF

You're actually very close to getting everything working.  You shouldn't use the extension ".mod" for any source code.  Your file testmodule.mod should actually be named testmodule.f90.  The compiler will generate a file testmodule.mod itself based on your source code in the modules subdirectory in your project's directory.

Module files are created by the compiler, and, generally speaking, they aren't human-readable.  The source code for the modules, however, just needs to be stored in Fortran source files ending in .f90 or something else appropriate (.f95 .f03 .f08 for example).

Jeff Armstrong
Approximatrix, LLC

Re: Modules in SF

Thank you very much!