So I've been coding something on 32-bit and yesterday I needed to build a dll and I had a couple of problems with that. Anyway I solved them here.
Unfortunately even if I thought that everything was working after all I found that wasn't the case when I moved my program and makefile on other computer what runs on 64bit, as you can guess what happened...
So my problem is related to relocation because of 64bit
/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
and here is my makefile
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}
I've tried to add -fPIC in CFLAGS, CPPFLAGS and even LDFLAGS. I've also tried add -fPIC before and after -shared flag.
-${CLINKER} -shared -fPIC -Wl,-soname,${SONAME} -o ${VERS} *.o ${PETSC_MAT_LIB}
But I'll just get a same error as previously.
If I use CFLAGS = -fPIC I'll get a bit same kind of error which is:
.../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.
I've read about all the topics what are even remotely similar with my problem but I've been unable to figure this out.
I encountered the same problem when I try to create a shared library which need to link a static library.
I solved the problem by adding -fPIC to CXXFLAGS to compile .o files which are archived in the static library.
The solution was to compile everything with -fPIC
, and link shared objects with -shared
.
Add -fPIC
to CFLAGS
or CXXFLAGS
for make-based projects.
Trying to compile xmlrpc-c-1.06.41 in CentOS 6.5, I have encountered same linking problem, which was solved by the following: In ./src/cpp, I have modified Makefile: line 142 to
CXXFLAGS = $(CXXFLAGS_COMMON) $(CFLAGS_PERSONAL) $(CADD) -shared -fPIC
More info regarding the flags can be found link
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