Msys2 -> f951.exe: Fatal Error: Reading module '...' at line 2 column 1: Unexpected EOF

Question

I am trying to use a module with gfortran 8.2.0 under Win 10 + Portable Msys2. This problem does not show up with gfortran 7.3.0 under Ubuntu 18.04LTS. After failing to compile my actual case, I put together

My MWE or MCVE:

• main.f90:

  program main_prog
  use testmod
  implicit none
  integer :: j
  end program main_prog
  

• mod_testmod.f90:

  module testmod
  implicit none
  <various statements>
  end module testmod
  

  depending on the contents of <various statements>, compilation worked or failed (see below).

Compilation

• mod_testmod.f90: Compiled ok, regardless of the combinations that I used for <various statements> (mod_testmod.o and testmod.mod were created with no errors):

  $ gfortran -g -c -o mod_testmod.o mod_testmod.f90
  

• main.f90: <various statements> (in mod_testmod.f90!) consisted of a few variable definitions:

  integer :: Npuntos=10             ! def 1
  double precision :: PI=3.1415296  ! def 2
  double precision :: T=4.0         ! def 3
  double precision :: T0=4.0        ! def 4
  double precision :: S0=4.0        ! def 5
  

  which were commented/uncommented. Depending on the combination, compilation worked or failed (it completely puzzles me, all should work). When failed, the error message was

  $ gfortran -g -c -o main.o main.f90
  f951.exe: Fatal Error: Reading module 'testmod' at line 34 column 62: Unexpected EOF
  compilation terminated.
  

  I wouldn't know if the line/column combination is of any use to track the problem.

  Combinations of unocmmented definitions that worked: (1), (1,4,5), (2,4,5), (3,4,5), (1,2,3,4), (1,2,4,5),

  Combinations of unocmmented definitions that failed: (none) (comment by High Performance Mark was right), (4,5), (1,3,4,5), (1,2,3,4,5),

  These are the combinations I tried, enough to have me completely lost on what's going on.

How can I solve this?

Answer 1

It seems that this problem is caused by the search rule of msys2. This error will emerge as long as there exists any invalid path before the location of msys64\mingw64\bin in path of Environment Variables.

You can solve this problem either by removing those invalid paths or moving the mingw64 path location to the first one.

Answer 2

I recommend upgrading your msys2 installation. I have tried your MCVE on my gfortran 8.3.0-2 (mingw64/mingw-w64-x86_64-gcc-libgfortran 8.3.0-2 (mingw-w64-x86_64-toolchain)) and windows 7 (I don't have a virtual machine with win10 yet) with msys2.

I updated my msys2 installation with pacman -Syu. Next I searched for gfortran via pacman -Ss gfortran and picked the x64 version.

To check I had the fortran:

$ whereis gfortran
gfortran: /mingw64/bin/gfortran.exe

I did this:

main.f90:

module testmod
implicit none
integer :: Npuntos=10             ! def 1
double precision :: PI=3.1415296  ! def 2
double precision :: T=4.0         ! def 3
double precision :: T0=4.0        ! def 4
double precision :: S0=4.0        ! def 5
end module testmod

and

mod_testmod.f90:

program main_prog
use testmod
implicit none
integer :: j
end program main_prog

Here is the log:

Ugun@thor MSYS /c/t/fortran
$ gfortran -g -c -o mod_testmod.o mod_testmod.f90

Ugun@thor MSYS /c/t/fortran
$ ls
main.f90  mod_testmod.f90  mod_testmod.o  testmod.mod

Ugun@thor MSYS /c/t/fortran
$ gfortran -g -c -o main.o main.f90

Note: for the sake of completness I have tried all the combinations you reported as failed and all were successful.

1. I think you should upgrade your MSYS2 env.
2. Upgrade your gfortran installation.