[petsc-users] Creating a dll on 64-bit environment

[Satish Balay]

Everything that goes into .so file should be built with -fPIC.

So you have to make sure MPI/PETSc are built with -fPIC flag. One way
to do this is to build woth PETSc and MPI as shared libraries.

Not sure what MPI you are using - but wrt PETSc - use the configure
option --with-shared-libraries=1

Satish

On Sat, 10 Mar 2012, Markus Iivonen wrote:

> Hello,
> 
> I've written a program on 32-bit environment and I want to use a dll. Everything worked fine until I uploaded the code on the other machine which run 64-bit os.
> At first I got an error:
> 
> "/usr/bin/ld: MyClass.o: relocation R_X86_64_32S against `.rodata' can not be used when making a shared object; recompile with -fPIC
> MyClass.o: could not read symbols: Bad value"
> 
> what was new for me because I haven't worked on 64bit environment before. Anyway at first I just tried to modify "-${CLINKER} -shared -Wl,-soname,${SONAME} -o ${VERS}   *.o  ${PETSC_MAT_LIB}" as "-${CLINKER} -shared -fPIC -Wl,-soname,${SONAME} -o ${VERS}   *.o  ${PETSC_MAT_LIB}"
> 
> even after that I got the same error, after that I added -fPIC to CFLAGS and the error changed:
> 
> "../petsc/petsc-3.2-p6/arch-linux2-cxx-debug/lib/libpetsc.a(err.o): relocation R_X86_64_32 against `ompi_mpi_comm_self' can not be used when making a shared object; recompile with -fPIC"
> 
> So here is my current makefile
> 
> 
> CFLAGS          = - fPIC
> CCPPFLAGS       =
> LOCDIR          = /home/user/petsc/project/
> EXAMPLESC       = x1.cpp x2.cpp x3.cpp
> PETSC_DIR 	= /home/user/petsc/petsc-3.2-p6/
> 
> MYLIB           = -L/home/user/petsc/project/opt/lib/ -libmyclass
> LIBADD          = /.../user/petsc/project/opt/lib/
> 
> VERS            = libmyclass.so.1.0
> SONAME          = libmyclass.so.1
> SOWOV           = libmyclass.so
>  
> include ${PETSC_DIR}/conf/variables
> include ${PETSC_DIR}/conf/rules
> 
> 
> 
> 
> MyProgram: main.o chkopts
>     -${CLINKER} -o $@ $< ${MYLIB} ${PETSC_MAT_LIB}
>     ${RM} main.o
> 
>     export LD_LIBRARY_PATH=${LIBADD}:$LD_LIBRARY_PATH
> 
> LibMyProgram.so: MyClass.o  chkopts
>     -${CLINKER}  -shared -Wl,-soname,${SONAME} -o ${VERS}   *.o  ${PETSC_MAT_LIB}
> 
>     mv ${VERS} ${LIBADD}
>     ln -sf ${LIBADD}${VERS} ${LIBADD}${SOWOV}
>     ln -sf ${LIBADD}${VERS} ${LIBADD}${SONAME}
> 
> So would there be any kind of solution to this problem ?
> 
> Thank You.
> 
> Sincerely Markus Iivonen