undefined reference to boost::log::v2_mt_posix about log

[Lastique]

The problem is likely mismatch between the library you're compiling for and your linker selects. v2s_mt_posix means you're compiling for the static library of Boost.Log and the linker is probably using the shared library by default.

If you want to link with the static library, you should explicitly specify it with the full path and no -l switch in the command line (e.g. gcc foo.o /usr/lib/libboost_log.a) or make sure no shared library is found by the linker. I don't know if CMake offers an easy way to do this.

If you want to link with the shared library then you should define BOOST_LOG_DYN_LINK or BOOST_ALL_DYN_LINK. See here.

[sflis]

For any of you that have these issues when compiling against static boost libraries the issue is actually that the FindBoost module in cmake is broken (see https://gitlab.kitware.com/cmake/cmake/-/issues/20638). The dependencies set for Boost::log are wrong in the find module as Boost::log_setup depends on Boost::log not the other way around.

Unfortunately I haven't figured out a clean workaround for this. Adding the libraries (not the targets) manually in the correct order solves the linker error, however it screws up the cmake configuration export.

[a-r-db]

The following worked for me.

cmake_minimum_required(VERSION 3.16)
project(PROJECT_NAME)
set(CMAKE_CXX_STANDARD 20)

find_package(Boost 1.71 REQUIRED COMPONENTS log_setup log)
add_executable(PROJECT_NAME main.cpp)

target_link_libraries(PROJECT_NAME ${Boost_LIBRARIES})

[bkda]

Need your help,many thanks.

[bkda]

I tried many ways, even specify full path, /usr/local/lib/libboost_log_setup.a /usr/local/lib/libboost_log.a still don't work.

It wastes me too much time.

[Lastique]

Does the linker issue any errors, like when it can't find the libraries you specify? If not, can you see the symbol names in the static libraries? In particular, the namespace name in the symbols is of interest. Using the link I posted, you can see the difference in the namespace names and adjust your config accordingly.

[bkda]

No, I can't see any errors, it just tells me Undefined symbols for architecture x86_64.

I added add_definitions(-DBOOST_LOG_DYN_LINK) into cmakelists.txt and it works on linux but on my mac ,it still doesn't work.

[Lastique]

Sorry, but I can't suggest anything helpful except to inspect your static libraries to see what's wrong with them. As a wild guess, is it possible that the libraries are 32-bit?

You can also try building Boost yourself.

[enhering]

Same on my MAC. Tried all solutions to fix it, but could not. I'm using Sierra and Boost 1.70.

[Divyank004]

Is anyone able to find the solution for the above issue in MAC

[amosialek]

I've added add_definitions(-DBOOST_LOG_DYN_LINK) and still getting the same error.
BOOST 1.71.0
Ubuntu 18.04.3

CMakeLists:

`
cmake_minimum_required(VERSION 3.10.0)

add_executable(Graphessor main.cpp)
find_package(Threads REQUIRED)
target_link_libraries (Graphessor Threads::Threads)
add_definitions(-DBOOST_LOG_DYN_LINK)
target_link_libraries (Graphessor Models)
target_link_libraries (Graphessor IO)
target_link_libraries (Graphessor Logic)
find_package(Boost COMPONENTS program_options REQUIRED)
INCLUDE_DIRECTORIES( ${Boost_INCLUDE_DIR} )
TARGET_LINK_LIBRARIES( Graphessor ${Boost_LIBRARIES} )
`

[luke-pefi]

@a93h 's solution didn't work for me. But this did the trick:

find_package(Boost 1.73 REQUIRED COMPONENTS log)
find_library(loglib libboost_log.a 3rdparty/boost_1_73_0/stage/lib)
target_link_libraries(Boost::log INTERFACE ${loglib})

This adds an additional instance of libboost_log at the end of the compiler line when linking.
Obviously change libboost_log.a to boost_log if you want the shared library version, and put your own path to the boost libraries dir.

[adityaprakash75]

Anyone got any solid fix for this on MAC??