Link statically a library when building a shared one lead to -fPIC error

Question

I'm trying to build a shared library (Aeron media driver) and I need to have one of its dependency linked statically (libbsd.a).

I have updated the original CMakeLists.txt in order to have this in the following way :

add_library(libbsd STATIC IMPORTED)
set_target_properties(libbsd PROPERTIES IMPORTED_LOCATION /usr/lib/x86_64-linux-gnu/libbsd.a)
set_target_properties(libbsd PROPERTIES 
    INTERFACE_INCLUDE_DIRECTORIES /usr/include)

target_link_libraries(
    aeron_driver
    ${CMAKE_DL_LIBS}
    libbsd
    ${AERON_LIB_UUID_LIBS}
    ${AERON_LIB_M_LIBS}
    ${AERON_LIB_ATOMIC_LIBS}
    ${CMAKE_THREAD_LIBS_INIT}
    ${AERON_LIB_WINSOCK_LIBS})

Unfortunaly CMake output this error :

/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libbsd.a(getentropy.o): relocation R_X86_64_PC32 against symbol `getentropy' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: bad value
collect2: error: ld returned 1 exit status

I have tried several ways of setting the option but no ones work

For instance:

target_compile_options(libbsd INTERFACE -fPIC)

still lead to the same error.

How to properly set this compiler flag ? Do I have to set this option on the aeron_driver target or on libbsd target ?

You cannot set any compiler flags on `IMPORTED` targets because they have already been built. They are taken as-is. — Friedrich, May 04 '23 at 16:18
I need to compile libbsd.a myself to be able to set this option ? @Friedrich — Guillaume Paris, May 04 '23 at 16:20
If it needs to be built with `-fPIC` (and it isn't) then yes. — Friedrich, May 04 '23 at 16:24
A compiler always builds shared libraries built with `-fPIC`. If a shared library wants to link with a static one, then given static library should be built with `-fPIC`. That is, for being able to link your shared library with `libbsd.a`, the latter should be build with `-fPIC`. — Tsyvarev, May 04 '23 at 17:58

Link statically a library when building a shared one lead to -fPIC error

0 Answers0