CODEWITHSUNDEEP
gcccmakeg++caffe
user1245262
user1245262

Reputation: 7505

Caffe build gives GCC Link Error "can not be used when making shared object.; recompile with -fPIC"

I'm trying to install caffe, using CMake, but when I run make all (after running cmake .. from a build directory) I get the following error:

me@gimli:~/Downloads/caffe/build$ make all
[  1%] Built target caffeproto
[  1%] Linking CXX shared library ../../lib/libcaffe.so
/usr/bin/x86_64-linux-gnu-ld: /usr/local/lib/libleveldb.a(db_impl.cc.o): relocation R_X86_64_PC32 against symbol `_ZN7leveldb10EnvWrapper8ScheduleEPFvPvES1_' can not be used when making a shared object; recompile with -fPIC
/usr/bin/x86_64-linux-gnu-ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
src/caffe/CMakeFiles/caffe.dir/build.make:40060: recipe for target 'lib/libcaffe.so.1.0.0' failed
make[2]: *** [lib/libcaffe.so.1.0.0] Error 1
CMakeFiles/Makefile2:267: recipe for target 'src/caffe/CMakeFiles/caffe.dir/all' failed
make[1]: *** [src/caffe/CMakeFiles/caffe.dir/all] Error 2
Makefile:129: recipe for target 'all' failed
make: *** [all] Error 2

I don't really understand CMake, but gather that somewhere I'm supposed to add -fPIC to a gcc command. But, I have no idea where I should make this change, or if there's somewhere in Cmake where I should tell it to construct the gcc command correctly.

How can I force CMake to create/use a gcc command with the -fPIC option, or is there something else entirely I should be doing?

Upvotes: 0

Views: 605

Answers (1)

Tsyvarev
Tsyvarev

Reputation: 65928

The error is not from CMake but from the linker. It actually tells, that:

You cannot build shared library libcaffe.so with PIC (Position independent code) feature and link it with the static library libleveldb.a compiled without this feature.

Possible solutions are:

  1. Get shared version of the static library (libleveldb.a in your case), so it will be compiled with PIC. This is what the error message suggests you.

  2. Instead of building shared library (Caffe in your case), build static one, without using of PIC. Note, that in this case your will face with similar issues when trying to use resulted library in the future shared libraries.

    For most CMake projects forcing the building static libraries can be performed with:

     cmake -DBUILD_SHARED_LIBS=OFF <other parameters>

Strictly speaking, PIC feature is independent from the type (shared or static) of a library. So you may have a static library with PIC, or build a shared library without it.

For many CMake projects you may control PIC feature of the created libraries with

cmake -DPOSITION_INDEPENDENT_CODE=<ON|OFF> <other parameter>

Upvotes: 2

Related Questions