How to build static library with bundled dependencies - CMake - c++

I am currently using CMake to create a static library which utilizes a few of the static libraries from OpenCV 4 ( core imgcodecs video highgui imgproc ). My intention is to be able to bundle all of the required OpenCV static libraries into my own library so that I can distribute it as one library. Additionally, I want for the user of my library to not have to install OpenCV 4 on their system (but do not mind if the user has to do simple installs using apt-get install). I know there are tools for bundling static libraries (such as using ar for linux).
However, where I really am having the issue is with all the dependencies of OpenCV (such as libjpeg, libpng, etc). I don't necessarily mind if these libraries are bundled with mine or linked dynamically as they are relatively easy to install (can be installed with sudo apt-get install, whereas opencv4 needs to be built from source).
What is the best way to go about doing this?
This is my current CMakeLists.txt
It is currently working, but that is because I am using find_package(OpenCV REQUIRED) (which defeats the purpose of what I am trying to do). When I remove that line, the linker complains about not being able to find the OpenCV dependencies.
cmake_minimum_required(VERSION 2.8)
project(myproject)
set(CMAKE_CXX_STANDARD 14)
include_directories(${CMAKE_CURRENT_LIST_DIR}/include)
link_directories(${CMAKE_CURRENT_LIST_DIR}/lib)
find_package(OpenMP REQUIRED)
find_package(OpenCV REQUIRED)
set(JSON_BuildTests OFF CACHE INTERNAL "")
add_subdirectory(nlohmann_json)
list(APPEND LINKER_LIBS opencv_core opencv_highgui opencv_video opencv_imgcodecs libmxnet.so libncnn.a nlohmann_json::nlohmann_json)
file(GLOB SRC${CMAKE_CURRENT_LIST_DIR}/src/*.cpp${CMAKE_CURRENT_LIST_DIR}/main.cpp)
add_library(myproject ${SRC})
target_link_libraries(myproject ${LINKER_LIBS} ${OpenMP_CXX_FLAGS})
To elaborate on my question. I build my project which generates libmyproject.a. I then take this library and will eventually extract the symbols from the OpenCV libs (libopencv_core.a libopencv_highgui.a libopencv_imgcodecs.a libopencv_video.a) and add them to my lib (for the time being, I have not yet done this step, which is why in the below example I am linking libopencv_*). I then use my library in a new project, for which the CMakeLists.txt is shown below:
cmake_minimum_required(VERSION 2.8)
project(myproject-driver)
set(CMAKE_CXX_STANDARD 14)
include_directories(${CMAKE_CURRENT_LIST_DIR}/include)
link_directories(${CMAKE_CURRENT_LIST_DIR}/lib)
find_package(OpenMP REQUIRED)
add_executable(myproject-driver main.cpp)
target_link_libraries(myproject-driver myproject libncnn.a ${OpenMP_CXX_FLAGS} libmxnet.so libopencv_core.a libopencv_highgui.a libopencv_imgcodecs.a libopencv_video.a)
Building this generates the following errors:
Linking CXX executable myproject-driver
/usr/bin/ld: /home/nchafni/Cyrus/myproject/lib/libopencv_imgcodecs.a(grfmt_jpeg.cpp.o): undefined reference to symbol 'jpeg_default_qtables##LIBJPEG_8.0'
//usr/lib/x86_64-linux-gnu/libjpeg.so.8: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
How can I fix this. Is there some CMake command which will link all these dependencies for me? Do I need to manually track down each dependency of those libopencv_* libs and link those manually? Once again, this is assuming that the person using libmyproject.a can't use find_package(OpenCV REQUIRED) as it won't be defined as they have not installed OpenCV on their machine.

First of all, don't use the super old and outdated version 2.8 of CMake. CMake 3.x is so much more powerful and pretty straightforward to use.
Some tips for modern CMake.
Don't use file(GLOB), see here why that is.
Don't use directory wide instructions, rather use target instructions, e.g. target_include_directories vs. include_directories.
Don't use string variables like ${<PACKAGE_NAME>_LIBRARIES}, rather use targets, e.g. <Package_NAME>::lib
When using targets instead of string variables, all the properties (including LINK_INTERFACE) of that target will be populated to the library/executable when calling target_link_libraries, so no more include_directories,link_directories, etc.
myproject
cmake_minimum_required(VERSION 3.14)
project(myproject)
set(CMAKE_CXX_STANDARD 14)
find_package(OpenMP REQUIRED)
find_package(OpenCV REQUIRED)
set(JSON_BuildTests OFF CACHE INTERNAL "")
add_subdirectory(nlohmann_json)
set(SOURCES ...) # list all the source files here
add_library(myproject ${SOURCES})
target_include_directories(myproject PUBLIC # give it a scope
${CMAKE_CURRENT_LIST_DIR}/include
)
target_link_libraries(myproject PUBLIC # give it a scope
opencv_core # using the target, you will get all LINK_LIBRARIES
opencv_highgui
opencv_video
opencv_imgcodecs
libmxnet.so # where is this coming from?
libncnn.a # where is this coming from?
nlohmann_json::nlohmann_json
OpenMP::OpenMP_CXX ## linking against a target, CXX_FLAGS will be populated automatically
)
myprojec-driver
cmake_minimum_required(VERSION 3.14)
project(myproject-driver)
set(CMAKE_CXX_STANDARD 14)
add_executable(myproject-driver main.cpp)
target_link_libraries(myproject-driver PUBLIC # give it a scope
myproject # gets all dependencies through the LINK_INTERFACE
)

Related

Qt Creator Error: cannot find -lopencv_imgcodecs

I have installed opencv, qt, qt creator, cmake on ubuntu 15.10 through VMware on windows.
The opencv is installed in this directory: /home/majidalaeinia/opencv/
The project repository is cloned in this directory: /home/majidalaeinia/Desktop/imgwarp-opencv/
I want to run the project through its CMakeLists.txt in qt creator and when I press Build now on qt creator, I get the following errors:
error: cannot find -lopencv_imgcodecs
error: collect2: error: ld returned 1 exit status
Where is the problem and how can I solve it?
# Majid Alaeinia, from the CMakeLists.txt file you posted it is not specified how CMAKE should find the libraries requested from your project. Also there are no target_link_libraries declared so CMAKE does not know where to link them. Hopefully the following small example template should be helpful for your project:
cmake_minimum_required (VERSION 3.1)
project(yourProject)
find_package( OpenCV REQUIRED )
find_package( Qt5 REQUIRED COMPONENTS Sql )
### this is for c++11
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
set(CMAKE_INCLUDE_CURRENT_DIR ON)
### QT stuff if you want a GUI
set(CMAKE_AUTOMOC ON) # autogenerate qt gui features
set(CMAKE_AUTORCC ON) # used for QT resource Files (if you need)
## Additional operation...
# From here you are specifically linking all OpenCV libraries and executables
### Add executables
add_executable(yourExecutable main/main.cpp ui/res/res.qrc ${SRCS} ${UI_HDRS} ${UI_SRCS})
target_link_libraries (yourProject example Qt5::Widgets ${OpenCV_LIBS} Qt5::Sql)
### Add Library
add_library(yourProject_lib SHARED ${SRCS} ${UI_HDRS})
target_link_libraries (yourProject_lib example Qt5::Widgets ${OpenCV_LIBS})
# Majid Alaeinia,I uploaded the repository and went through the code. if you go inside the demo folder and you change the present CMakeLists.txt file with the one I provided below it should compile (It does compile on mine with the provided changes):
project(demo)
cmake_minimum_required(VERSION 2.6)
find_package(Qt5 REQUIRED COMPONENTS Widgets Core)
FIND_PACKAGE( OpenCV REQUIRED )
include_directories(${QT_INCLUDES} ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_SOURCE_DIR}/lib ${CMAKE_CURRENT_SOURCE_DIR})
set(demo_SRCS main.cpp projfile.cpp deformwin.cpp myimage.cpp singlephotoview.cpp pointspaint.cpp)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
set(CMAKE_INCLUDE_CURRENT_DIR ON)
#qt5_automoc(${demo_SRCS})
QT5_WRAP_CPP(QOBJ_CPP ${demo_SRCS})
qt5_wrap_ui(helloworld_FORMS_HEADERS deformwin.ui)
add_executable(demo ${demo_SRCS} ${helloworld_FORMS_HEADERS})
target_link_libraries(demo ${QT_QTCORE_LIBRARY} ${QT_QTGUI_LIBRARY} imgwarp-lib opencv_core opencv_imgproc opencv_imgcodecs)
The code in the repository is an old code and still carries Qt4 as main wrappers. I think you probably have Qt5 installed on your computer and in fact the code I provided it will work for Qt5. Use it as a guideline for the other CMakeLists.txt file present inside src folder and change accordingly.
CMake will compile but because it was used Qt4 you need to figure out the most important modules to add, for example the new standard for including QtGui/QApplication is usually substituted by QtWidgets/QApplication
I also wanted to leave my previous answer in case you need a starting point or a initial template. I hope this clarifies a bit more and can get you move forward for your project.

proper way to write a CMakeLists referencing HDF5 in Windows

I've already downloaded an built HDF5 under Windows using CMake, I also generated an installer to install it under Program Files.
Below the CMakeLists.txt I wrote to be able to use HDF5 in a program I already wrote under Linux :
cmake_minimum_required(VERSION 2.8)
project(Hdf5DataFeed)
add_definitions(-DWINDOWS)
find_package(HDF5)
FIND_LIBRARY(HDF5_HL_LIBRARY hdf5_hl)
FIND_LIBRARY(ZLIB zlib)
find_library(ZMQ_LIB zmq)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
include_directories(${ZMQ_LIB_INCLUDE})
aux_source_directory(. SRC_LIST)
add_executable(${PROJECT_NAME} ${SRC_LIST})
target_link_libraries(${PROJECT_NAME} ${ZLIB} "C:/Program Files/HDF_Group/HDF5/1.10.1/lib/libszip.lib" ${VTK_LIBRARIES} ${ZMQ_LIB} ${HDF5_LIBRARIES} ${HDF5_HL_LIBRARY} Qt5::Core Qt5::Gui Qt5::Widgets)
target_include_directories(${PROJECT_NAME} PRIVATE ${HDF5_INCLUDE_DIRS})
As you can see above, to link HDF5 under Visual Studio, I needed Zlib, Szip (that I had to enter an absolute path to it, I don't like that), HDF5 library and the HDF5 High Level (Lite) library.
These libraries are located under C:\Program Files\HDF_Group\HDF5\1.10.1\lib :
libhdf5.lib <============
libhdf5.settings
libhdf5_cpp.lib
libhdf5_hl.lib <=====
libhdf5_hl_cpp.lib
libhdf5_tools.lib
libszip.lib <=== ????
libzlib.lib <====
I use CMake-Gui to inform CMake of the libraries path (except for Szip, I don't know why CMake doesn't know about it, and why I don't have the possibility to just feed CMake the library directory instead of indicating the path of few of them).
I want to use CMake-GUI to inform CMake of Szip library path, but this last doesn't create an entry of it, I only have these entries related to HDF5 :
I'm having troubles with HDF5 also under Ubuntu (see this question : hdf5.h no such file or directory under Ubuntu and CMake).
For now, it's only under CentOS 7 that I didn't encounter any issues with HDF5.
If someone can give me/us a final solution that works both on Windows and Ubuntu that would be great !
Does this solution work for you?
cmake_minimum_required(VERSION 2.8)
project(Hdf5DataFeed)
# necessary?
add_definitions(-DWINDOWS)
find_package(HDF5 REQUIRED COMPONENTS C CXX HL)
find_package(ZLIB REQUIRED)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
find_library(ZMQ_LIB zmq)
include_directories(${ZMQ_LIB_INCLUDE} ${HDF5_INCLUDE_DIR}
${ZLIB_INCLUDE_DIRS})
aux_source_directory(. SRC_LIST)
add_executable(${PROJECT_NAME} ${SRC_LIST})
target_link_libraries(${PROJECT_NAME} ${HDF5_LIBRARIES}
${HDF5_HL_LIBRARIES} ${ZLIB_LIBRARIES} ${VTK_LIBRARIES}
Qt5::Core Qt5::Gui Qt5::Widgets ${ZMQ_LIB})
Recommendation 1: Surely, there is a way to find Qt5 via find_package, i.e.,
find_package(Qt5 COMPONENTS Core Widgets REQUIRED)
and then add the correct variables to include_directories and target_link_libraries. Not sure whether such a possibility exists for the zmq library, though.
Recommendation 2: I think the call the aux_source_directory should be avoided in most cases. Create an explicit list of your source files instead.
For libszip, adding a find_library is better than putting an absolute link to it. For ZLib, it is preferable to use find_library as find_package will require you to feed CMake with an include directory which is not required for HDF5. Finally, it is preferable to use find_package for ZMQ, otherwise, we need to add manually the entry "ZMQ_LIB_INCLUDE".

CMake user built libraries; cannot specify link libraries for target

I'm building a project in Cpp that will communicate with my Java apps via rabbitmq and post updates to twitter. I'm using a few libraries from github
rabbitmq-c
Rabbit installed to /usr/local/lib64
jansson - json library
I installed this a while back for another project, went to /usr/local/lib
twitcurl - C lib for Twitter API
Got installed to /usr/local/lib
If it matters, I'm using CLion as my IDE, which displays jansson and rabbit under auto-complete when defining includes - so that's picking the libs off my system somehow
e.g.
#include <jansson.h>
#include <amqp.h>
I link them using the target_link_libraries(name libs...) and I see output saying
build$ cmake ..
CMake Error at CMakeLists.txt:30 (target_link_libraries):
Cannot specify link libraries for target "twitcurl" which is not built by
this project.
I set LD_LIBRARY_PATH
export LD_LIBRARY_PATH=/usr/local/lib:/usr/local/lib64
I try to set the CMAKE_LIBRARY_PATH to include usr/local/lib and lib64 but doesn't seem to have any effect. Here's my CMakeLists.txt file
#
# This is a CMake makefile. You can find the cmake utility and
# information about it at http://www.cmake.org
#
cmake_minimum_required(VERSION 2.6)
set(PROJECT_NAME twitterUpdater)
set(SOURCE_FILES main.cpp)
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
set(CMAKE_LIBRARY_PATH ${CMAKE_LIBRARY_PATH} "/usr/local/lib"
"/usr/local/lib64")
project(${PROJECT_NAME})
find_package(X11 REQUIRED)
find_package(OpenCV REQUIRED)
IF (X11_FOUND)
INCLUDE_DIRECTORIES(${X11_INCLUDE_DIR})
LINK_LIBRARIES(${X11_LIBRARIES})
ENDIF ( X11_FOUND )
IF (OpenCV_FOUND)
include_directories(${OpenCV_INCLUDE_DIRS})
link_libraries(${OpenCV_LIBS})
ENDIF(OpenCV_FOUND)
add_executable(${PROJECT_NAME} ${SOURCE_FILES})
target_link_libraries(${project_name} twitcurl jansson rabbitmq)
What's confusing me is another project I have uses jansson by simply adding it here TARGET_LINK_LIBRARIES(${project_name} dlib jansson)
What did I miss?? Thanks
CMake variables are case sensitive, thus the variable ${project_name} results in an empty string. Use ${PROJECT_NAME} instead, i.e.:
target_link_libraries(${PROJECT_NAME} twitcurl jansson rabbitmq)
Running CMake with the flag --warn-uninitialized helps you detect mistakes like this.

Static linking DCMTK library

I use DCMTK in my application and for compilation use cmake file. cmake finds all libraries (at least headers, because in compiles source files to .o files) the only problem is that during linking it tries to find dynamic libraries for DCMTK. I compiled one as static, so I do not have .so files. As a result it gives me error :No rule to make target /usr/lib/libdcmdata.so, needed by dcm_seg. Stop.
I use Ubuntu 14.04 x64.
It confuses me pretty much. So, what's the problems?
cmake file:
cmake_minimum_required(VERSION 2.6)
project(dcm_segm)
set(CMAKE_CXX_FLAGS "-std=c++0x ${CMAKE_CXX_FLAGS} -g -ftest-coverage -fprofile-arcs")
set(Boost_USE_STATIC_LIBS ON)
set(OpenCV_USE_STATIC_LIBS ON)
set(DCMTK_USE_STATIC_LIBS ON)
set(OpenCV_STATIC ON)
find_package( VTK REQUIRED )
find_package( OpenCV REQUIRED )
find_package( Boost COMPONENTS system filesystem REQUIRED )
find_package( DCMTK REQUIRED )
include(${VTK_USE_FILE} )
link_directories(${OpenCV_LIB_DIR})
add_executable(dcm_seg main.cpp DICOMin.cpp Ensemble.cpp Ensemble3dExtension.cpp point_3d.cpp RegionGrow.cpp)
target_link_libraries(dcm_seg ${VTK_LIBRARIES} ${OpenCV_LIBS} ${DCMTK_LIBRARIES} ${Boost_LIBRARIES})
Can you check the content of ${DCMTK_LIBRARIES} (it should be a list of paths to DCMTK static libraries) ?
you can also check the following CMake entries during the CMake configuration:
DCMTK_DIR /path/to/DCMTK/install
DCMTK_config_INCLUDE_DIR /path/to/DCMTK/install/include/dcmtk/config
DCMTK_dcmdata_INCLUDE_DIR /path/to/DCMTK/install/dcmdata/include/dcmtk/dcmdata
DCMTK_dcmdata_LIBRARY_DEBUG /path/to/DCMTK/install/dcmdata/libsrc/libdcmdata.a
DCMTK_dcmdata_LIBRARY_RELEASE /path/to/DCMTK/install/dcmdata/libsrc/libdcmdata.a
[...]
Another hint: I noted in the past that find DCMTK from a build instead of an install not always works properly.
If you have trouble finding DCMTK with the script provided with CMake
(${DCMTK_LIBRARIES} doesn not content the path to you static DCMTK libs for example) you can try to use this alternative script

Can I make a library from multiple targets?

I'm trying to learn cmake and have started converting an old make project over to cmake. Here is a simplified version of the directory structure I now have:
CMakeLists.txt
src/
CMakeLists.txt
main.cpp
core/
CMakeLists.txt
/sourcecode, other cmakes, etc.
test/
CMakeLists.txt
someTest.cpp
Currently, in my root CMakeLists.txt file I simply have this:
cmake_minimum_required(VERSION 2.8)
project(all)
add_subdirectory(src)
add_subdirectory(test)
What I wanted to do, was have a library created by core/CMakeLists.txt that can be used by both src/CMakeLists.txt to build the main executable, but also loaded by test/CMakeLists to build the unit tests.
So my src/core/CMakeLists.txt file currently looks sort of like this:
cmake_minimum_required(VERSION 2.8)
project(core)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wpedantic -Wreorder -DBOOST_TEST_DYN_LINK -DBOOST_LOG_DYN_LINK ")
#some other directories in my core code:
add_subdirectory(display)
add_subdirectory(training)
add_subdirectory(utility)
#some packages I use...
find_package(Boost 1.55.0
COMPONENTS
log
program_options
serialization
thread
system
filesystem
REQUIRED)
find_package(GLUT REQUIRED)
find_package(OpenGL REQUIRED)
find_package(Eigen3 REQUIRED)
include_directories(
${PROJECT_SOURCE_DIR}
${EIGEN3_INCLUDE_DIR})
target_link_libraries(core
display
training
utility
${Boost_LIBRARIES}
${OPENGL_LIBRARIES}
${GLUT_LIBRARY}
${OpenMP_LIBRARIES})
So the idea is that I now have a core target I can simply link against to run my tests, and everything should work. However, when I try to build main, for example, I get:
Cannot specify link libraries for target "core" which is not built by this
project.
I thought this might be because core doesn't have a add_library command, but if I add add_library(core) I get this error:
You have called ADD_LIBRARY for library core without any source files. This typically indicates a problem with your CMakeLists.txt file
But I don't want to add any source files; I just want this target to link the targets in the core directory and produce a target I can link against from test.
Clearly I'm missing some core knowledge here, either with cmake or the toolchain itself. Help is appreciated :)
If you only want to create a core target without source files, you need to declare it like an INTERFACE target. So, try to add the following code to your src/core/CMakeLists.txt:
cmake_minimum_required(VERSION 3.0) # REQUIRED 3.x.x version
project(core)
...
# Here declare your core_interface target
add_library(core_interface INTERFACE)
target_link_libraries(core_interface INTERFACE
display
training
utility
${Boost_LIBRARIES}
${OPENGL_LIBRARIES}
${GLUT_LIBRARY}
${OpenMP_LIBRARIES})
As you can see, if you make this, you'll need to upgrade your CMake installed version.
Then, you'll build your tests or any executable, linking with this interface target directly:
add_executable(main main.cpp)
target_link_libraries(main core_interface)