Re: Linking Fortran to C++

[Tim Prince <timothyprince at sbcglobal dot net>]

Americo Barbosa da Cunha Junior wrote:
> I've trying to link a Fortran code to a C++ code.
>
> First I create the object files for both languages:
>
> g77  -c  ckinterp.f   math.f   xerror.f  cklib.f  vode.f  conp.f
> g++  -c  linear_alg.cpp  teste.cpp
>
> Than I use the g++ to link:
>
> g++  -o  jac *.o -lg2c -lm
>
> The GCC returns a message like:
>
> cklib.o: In function `ckcomp_':cklib.f:(.text+0x2b43): multiple 
> definition of `ckcomp_'
> ckinterp.o:ckinterp.f:(.text+0xa9b3): first defined here
> cklib.o: In function `ifirch_':cklib.f:(.text+0x17d58): multiple 
> definition of `ifirch_'
> ckinterp.o:ckinterp.f:(.text+0xa8aa): first defined here
> /usr/bin/ld: Warning: size of symbol `ifirch_' changed from 139 in 
> ckinterp.o to 164 in cklib.o
> cklib.o: In function `ilasch_':cklib.f:(.text+0x17dfc): multiple 
> definition of `ilasch_'
> ckinterp.o:ckinterp.f:(.text+0xa935): first defined here
> /usr/bin/ld: Warning: size of symbol `ilasch_' changed from 126 in 
> ckinterp.o to 156 in cklib.o
> cklib.o: In function `ipplen_':cklib.f:(.text+0x18654): multiple 
> definition of `ipplen_'
> ckinterp.o:ckinterp.f:(.text+0xb1c7): first defined here
> cklib.o: In function `ipparr_':cklib.f:(.text+0x1827b): multiple 
> definition of `ipparr_'
> ckinterp.o:ckinterp.f:(.text+0xa491): first defined here
> /usr/bin/ld: Warning: size of symbol `ipparr_' changed from 1049 in 
> ckinterp.o to 985 in cklib.o
> cklib.o: In function `ippari_':cklib.f:(.text+0x17e98): multiple 
> definition of `ippari_'
> ckinterp.o:ckinterp.f:(.text+0xa0ae): first defined here
> conp.o: In function `MAIN__':conp.f:(.text+0x0): multiple definition of 
> `MAIN__'
> ckinterp.o:ckinterp.f:(.text+0x0): first defined here
> /usr/bin/ld: Warning: size of symbol `MAIN__' changed from 11317 in 
> ckinterp.o to 3528 in conp.o
> xerror.o: In function `xerrwv_':xerror.f:(.text+0xfc0): multiple 
> definition of `xerrwv_'
> vode.o:vode.f:(.text+0x7484): first defined here
> /usr/bin/ld: Warning: size of symbol `xerrwv_' changed from 457 in 
> vode.o to 593 in xerror.o
> /usr/bin/ld: cannot find -lg2c
> collect2: ld returned 1 exit status
If you do have multiple versions of the same subroutine (and Fortran 
MAIN) in your source code, you'll have to figure out which don't belong, 
and exclude them.
As you have 2 versions of Fortran main program, it's difficult to 
understand why you would use g++ to link.  Why not choose a Fortran, 
preferably an up to date gfortran, to run the whole show?  Something like
gfortran *.f *.cpp -lstdc++  (having selected the proper *.f)