Makefile Compiling Issue for Mixed C++ and Fortran Program

Question

This is my makefile :

    PROGRAM = mf2005-GPU.f

    # Define the Fortran compile flags
    F90FLAGS= -g -fopenmp
    F90= gfortran

    # Define the C compile flags
    # -D_UF defines UNIX naming conventions for mixed language compilation.
    CFLAGS= -D_UF -O3
    CC= gcc

    CPPFLAGS= -Dcpp_variable
    CXX= g++

    # Define GMG objects
    #
    GMG = r_vector.o\
      solvers.o\
      ccfd.o\
      mf2kgmg.o\

    # Define the libraries

    SYSLIBS= -lc
    USRLIB  = 
    CUDA_LIB64=/cm/shared/apps/cuda40/toolkit/4.0.17/lib64/
    LFLAGS = -L$(CUDA_LIB64) -lcuda -lcudart -lcusparse -lcublas -lpthread -lm -lcufft -lcurand -lnpp -lgomp 

    # Define all object files which make up MODFLOW

    OBJECTS = \
    dblas.o\
    gwf2bas7.o \
    de47.o \
    dlapak.o\
    pcg7.o \
    sip7.o \
    gmg7.o \
    mhc7.o \
    gwf2bcf7.o \
    gwf2lpf7.o \
    gwf2huf7.o \
    gwf2rch7.o \
    gwfuzfmodule.o \
    gwfsfrmodule.o \
    gwf2lak7.o \
    gwf2sfr7.o \
    gwf2uzf1.o \
    gwf2gag7.o \
    gwf2chd7.o \
    gwf2drn7.o \
    gwf2drt7.o \
    gwf2ets7.o \
    gwf2evt7.o \
    gwf2fhb7.o \
    gwf2ghb7.o \
    gwf2hfb7.o \
    gwf2ibs7.o \
    gwf2res7.o \
    gwf2riv7.o \
    gwf2str7.o \
    gwf2sub7.o \
    gwf2swt7.o \
    gwf2wel7.o \
    hufutl7.o \
    obs2bas7.o \
    obs2drn7.o \
    obs2ghb7.o \
    obs2riv7.o \
    obs2chd7.o \
    obs2str7.o \
    parutl7.o \
    gwf2mnw17.o \
    gwf2mnw27.o \
    gwf2mnw2i7.o \
    utl7.o \
    lmt7.o \
    gwf2hydmod7.o \
    upcg7.o \
    upcgc.o \
    upcg7lanczos.o \
    upcg7polya.o \
    upcg7polyu.o \
    mf2005-GPU.o \

    # Define Task Function

    all: mf2005-GPU

    # Define what mf2005

    mf2005-GPU: $(OBJECTS) $(GMG) 
-$(F90) $(F90FLAGS) -o mf2005-GPU $(OBJECTS) cuda_kernels.o $(GMG)  $(USRLIB)  $(SYSLIBS)    $(LFLAGS)

    # Object codes

    .f.o:
    $(F90) $(F90FLAGS) -c $<

    .c.o:
    $(CC) $(CFLAGS) -c $<


    .cpp.o:
    $(CXX) $(CPPFLAGS) -c $<

    #  end

This is how I compile cuda_kernels.cu nvcc -c -arch sm_20 -lcuda -lcudart -lcusparse cuda_kernels.cu

This is what I get for errors

    upcg7.o: In function `upcg7ar':
    /home/zhangmj/MF2005_MAKE/upcg7.f:731: undefined reference to `upcgc7_init_'
    upcg7.o: In function `upcg7ap':
    /home/zhangmj/MF2005_MAKE/upcg7.f:1272: undefined reference to `upcgc7_'
    upcg7.o: In function `upcg7da':
    /home/zhangmj/MF2005_MAKE/upcg7.f:1416: undefined reference to `upcgc7_final_'
    upcgc.o: In function `UPCGC7':
    upcgc.cpp:(.text+0xf6a): undefined reference to `SUPCGILU0A'
    collect2: ld returned 1 exit status
    make: [mf2005-GPU] Error 1 (ignored)

Following is upcg7.f (this is not my code, I download it from here) https://github.com/jdhughes-usgs/modflow-2005-upcg/blob/master/code/src/UPCG/upcg7.f

Following is upcgc.cpp and upcgc.h (this is not my code, I download it from here) https://github.com/jdhughes-usgs/modflow-2005-upcg/blob/master/code/src/UPCG/upcgc.cpp

**My question is ** SUPCGILU0A is the subroutine defined in upcg7.f. And subroutine SUPCGILU0A is called from the C++ program upcgc.cpp. upcgc7_init, upcgc7 and upcgc7_final are defined in upcgc.cpp, And these three are called from the fortran program upcg7.f.

I understand from my research that these are likely linker issues,or C++ and Fortran need to translate some function/routine from the other, but I cannot figure out what the problem is. Is there anyone out there who might have some insight into what the issue is?

haraldkl haraldkl · Accepted Answer · 2013-07-31T21:18:05

If the upcgc7 routines reside in the C code, they probably do not have the trailing underscore. The best way to deal with this is to make use of the ISO_C_BINDING interface in Fortran and declare the interfaces to these routines.

Makefile Compiling Issue for Mixed C++ and Fortran Program

1 Answers