Symbols found by the compiler not found by the linker

[sariyski__ted]

MacOS: High Sierra; Xcode: 10.1 ; Ifort: 18.0.5

Hi,

I have an issue building an application with intel18 on MacOS, which I do not have with gcc,

I have symbols defined in a module io, which are found by the compiler, but not from the linker.

Subroutine set_runtime_parameters()  ! ======> in headers.a

…

      use io,only:amr_log_file,output_dir

                 …

io.F90 is part of a headers.a library, which is passed to the linker, see below. Looking for a workaround, I copied the module files to the directory where the library headers.a is located, but it did not help. Do I miss a flag or something else? Any help is highly appreciated.

Thanks,

Ted

/opt/mpich321_intel18/bin/mpif90    -g -cpp  -O0  -check bounds -check format -zero  CMakeFiles/plotting.bin.dir/__/test_plotting.F90.o 

-o /Users/tesari/lynx/build/intel18_mpich321/ep /bin/plotting.bin

-L/Users/tesari/lynx/build/intel18_mpich321/ep /lib -lheaders                                  ! <==============

/opt/intel/compilers_and_libraries_2018.5.231/mac/compiler/lib/libirng.a

/opt/intel/compilers_and_libraries_2018.5.231/mac/compiler/lib/libdecimal.a -lc++

Undefined symbols for architecture x86_64:

  "_io_mp_amr_log_file_", referenced from:

      _amr_set_runtime_parameters_ in libparamesh.a(amr_set_runtime_parameters.F90.o)

  "_io_mp_output_dir_", referenced from:

      _amr_set_runtime_parameters_ in libparamesh.a(amr_set_runtime_parameters.F90.o)

ld: symbol(s) not found for architecture x86_64

[Steve_Lionel]

Which compiler compiled this .o and the .a? I suggest simplifying the build, taking mpif90 out of the loop, until you get it built. Please note that you cannot mix Fortran compilers (such as gfortran and ifort) in an application.

The module files (.mod) are not referenced during the link step.

[jimdempseyatthecove]

When you compile a source.f90 file that contains a module it produces two or more output files: You have the .mod files (think of these as pre-compiled headers) and .o (.obj) files:

!  ModuleTest.f90 
!
!  FUNCTIONS:
!  ModuleTest - Entry point of console application.
!

!****************************************************************************
!
!  PROGRAM: ModuleTest
!
!  PURPOSE:  Entry point for the console application.
!
!****************************************************************************
module ModuleWithProgram
    integer :: i_ModuleWithProgram
    contains
    subroutine sub_ModuleWithProgram
        print *,"ModuleWithProgram"
    end subroutine sub_ModuleWithProgram
end module ModuleWithProgram
    
program ModuleTest
    use ModuleWithProgram
    use ModuleOutsideProgram
    implicit none
    call sub_ModuleWithProgram
    call sub_ModuleOutsideProgram
end program ModuleTest

======================================

! Source1.f90 *** note name need not be same as module name
module ModuleOutsideProgram
    integer :: i_ModuleOutsideProgram
    contains
    subroutine sub_ModuleOutsideProgram
        print *,"ModuleOutsideProgram"
    end subroutine sub_ModuleOutsideProgram
end module ModuleOutsideProgram

================================

C:\test\ModuleTest\ModuleTest>dir /s/b
C:\test\ModuleTest\ModuleTest\Debug
C:\test\ModuleTest\ModuleTest\ModuleTest.f90                             Source of PROGRAM containing a module
C:\test\ModuleTest\ModuleTest\ModuleTest.vfproj
C:\test\ModuleTest\ModuleTest\ReadMe.txt
C:\test\ModuleTest\ModuleTest\Source1.f90                                Source of auxilliary file containing a module
C:\test\ModuleTest\ModuleTest\Debug\BuildLog.htm
C:\test\ModuleTest\ModuleTest\Debug\moduleoutsideprogram.mod             .mod file of module in Source of auxilliary file
C:\test\ModuleTest\ModuleTest\Debug\ModuleTest.exe                       .exe file of complete program with auxilliary
C:\test\ModuleTest\ModuleTest\Debug\ModuleTest.exe.intermediate.manifest
C:\test\ModuleTest\ModuleTest\Debug\ModuleTest.obj                       .obj file of Source of PROGRAM containing a module
C:\test\ModuleTest\ModuleTest\Debug\ModuleTest.pdb
C:\test\ModuleTest\ModuleTest\Debug\modulewithprogram.mod                .mod file created for module contained in Source of auxilliary file
C:\test\ModuleTest\ModuleTest\Debug\Source1.obj                          .obj file for (all) modules contained in Source of auxilliary file
C:\test\ModuleTest\ModuleTest\Debug\vc120.pdb

The above is from a Windows system, a similar layout occurs on Linux

You apparently are not linking in the .o file(s) that was(were) produced along with the module(s). Note, the .mod files take on the name of the module (one per module), the .o file(s) take on the file name containing the module(s).

Jim Dempsey