CODEWITHSUNDEEP
pythonc++boostcmake
Ashkan
Ashkan

Reputation: 1085

CMake boost also needs -lboost_* to work

I am trying to link my code to boost, python and armadillo. Here is the CMakeLists.txt I use

cmake_minimum_required(VERSION 3.3)

set(EXEC_NAME phases)
set(LIBS_NAME Hamilton)
project(${EXEC_NAME})

if(NOT CMAKE_BUILD_TYPE)
  set(CMAKE_BUILD_TYPE "Release")
endif()

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

set(LIB_HEADER point.h
               hamilton.h)
set(LIB_SOURCE  point.cpp
               hamilton.cpp)

add_library(${LIBS_NAME} SHARED ${LIB_SOURCE} ${LIB_HEADER})
add_library("${LIBS_NAME}_mod" MODULE ${LIB_SOURCE} ${LIB_HEADER})

set(HEADER_FILES point.h hamilton.h)
set(SOURCE_FILES main.cpp)
add_executable(${EXEC_NAME} ${SOURCE_FILES} ${HEADER_FILES})
target_link_libraries(${EXEC_NAME} ${LIBS_NAME})

find_package(Boost COMPONENTS python REQUIRED)
include_directories(${Boost_INCLUDE_DIRS})
target_link_libraries(${EXEC_NAME} ${Boost_LIBRARIES})
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -lboost_python")
set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -lboost_python")

find_package(Armadillo REQUIRED)
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -larmadillo")
set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -larmadillo")
include_directories(${ARMADILLO_INCLUDE_DIRS})
target_link_libraries(${EXEC_NAME} ${ARMADILLO_LIBRARIES})

find_package(PythonLibs REQUIRED)
include_directories(${PYTHON_INCLUDE_DIRS})
target_link_libraries(${EXEC_NAME} ${PYTHON_LIBRARIES})
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -lpython")
set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -lpython")

message(STATUS "Building in ${CMAKE_BUILD_TYPE} ...")

As you can see I am adding the flag -l... after each library. If I remove them then I get a linker error.

Is there any nice way to avoid this?

I use intel compiler icc but also tries clang and gcc clang doesn't need the extra -l... flags.

NOTE Only using target_link_libraries without the CMAKE_xxx_flags gives me a linker error. That is why I am asking this question.

I have cmake 3.3, boost 1.59 with boost-python and armadillo installed using homebrew

Update

The error I get is 

Reaping winning child 0x7fa188492f80 PID 47863 
Live child 0x7fa188492f80 (libHamilton.dylib) PID 47864 
Undefined symbols for architecture x86_64:
  "__ZN5boost6python15instance_holder10deallocateEP7_objectPv", referenced from:  
__ZN5boost6python7objects11make_holderILi3EE5applyINS1_12value_holderI8Hami    ltonEENS_3mpl7vector3IKdKmSB_EEE7executeEP7_objectdmm in hamilton.cpp.o

which is from linking to boost libraries.

Outputting the content of Boost_LIBRARIES gives me

/usr/local/lib/libboost_python-mt.dylib

on the other hand Boost_python_LIBRARY returns empty string

Upvotes: 0

Views: 357

Answers (1)

Slava
Slava

Reputation: 44258

As stated in FindBoost doc

target_link_libraries(${EXEC_NAME} ${Boost_LIBRARIES})

need to be used, remove 

set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -lboost_python")

etc

Check content of Boost_LIBRARIES variable:

 message( "Boost_LIBRARIES: ${Boost_LIBRARIES}" )

You may try to use Boost_python_LIBRARY variable instead, also Boost_python_LIBRARY_DEBUG or Boost_python_LIBRARY_RELEASE may work, in this case most probably your boost installation is somehow broken or at least not the way as expected by cmake module.

Update: your error shows that you have issue linking with multythread or shared version of boost_python. You can fix it by specifying:

set( Boost_USE_MULTITHREADED OFF )

or

set( Boost_USE_STATIC_LIBS ON )

before find_package or find the cause of that linking error.

Upvotes: 2

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