Cmake error: Cannot specify link libraries for target [duplicate] - c++

This question already has an answer here:
Build project with "experimental/filesystem" using cmake
(1 answer)
Closed 3 years ago.
I am trying to build a simple CMake project but I'm having problems understanding CMake or at least the error I get.
The project i made is divided in a couple directories.
The main one has this cmake:
cmake_minimum_required(VERSION 3.7.2)
project(Raytracer)
set(CMAKE_CXX_STANDARD 14)
add_subdirectory(src)
set(COMMON_INCLUDES ${PROJECT_SOURCE_DIR}/inc)
From there my project splits in 2 folders src and inc.
and in src i have the following cmake with the idea to global all subfolders:
FILE(GLOB sub-dirs RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *)
FOREACH(dir ${sub-dirs})
IF(IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/${dir})
ADD_SUBDIRECTORY(${dir})
ENDIF()
ENDFOREACH()
add_executable(raytracer main.cpp)
I also add the executable there which is in this main src folder.
From there on i want to be able to make sub folders adding with their own Cmake files and linking those files to my executable.
I have the following cmake:
set(OBJECTS
asdf.cpp
)
add_library(obj_files ${OBJECTS} ${COMMON_FILES})
target_link_libraries(raytracer obj_files)
but when I try to build I get the following error:
Cannot specify link libraries for target "raytracer" which is not built by this project.

Basically in Cmake file or toolchain.cmake the order of commands are important!
target_link_libraries() or target_include_directories() have to be always after add_executable()

Related

How to use Caffe library in C++ project with CMakeLists.txt

I'm trying to use Caffe in my C++ project which I compile with CMakeLists.txt, but it doesn't want to work. My only line in the code is
#include <caffe/caffe.hpp>
I compiled Caffe myself, it is installed in the directory "/home/tamas/caffe". My CMakeLists.txt looks like this so far:
cmake_minimum_required (VERSION 3.5)
include(FindPkgConfig)
project (main)
set (CMAKE_CXX_STANDARD 11)
set (CMAKE_CXX_STANDARD_REQUIRED TRUE)
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Werror -std=c++11 -pthread")
set (source_dir "${PROJECT_SOURCE_DIR}/src/")
set (OpenCV_DIR "/home/tamas/opencv/include/opencv2")
set (Caffe_DIR "/home/tamas/caffe")
file (GLOB source_files "${source_dir}/ssd_video.cpp")
find_package(OpenCV 4.4.0 REQUIRED)
include_directories(${OpenCV_INCLUDE_DIRS})
find_package(Caffe REQUIRED)
include_directories(${Caffe_INCLUDE_DIRS})
add_executable (main ${source_files})
target_link_libraries(main ${OpenCV_LIBS})
target_link_libraries(main ${Caffe_LIBRARIES})
The error is the following:
CMake Error at CMakeLists.txt:24 (find_package):
By not providing "FindCaffe.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "Caffe", but
CMake did not find one.
Could not find a package configuration file provided by "Caffe" with any of
the following names:
CaffeConfig.cmake
caffe-config.cmake
Add the installation prefix of "Caffe" to CMAKE_PREFIX_PATH or set
"Caffe_DIR" to a directory containing one of the above files. If "Caffe"
provides a separate development package or SDK, be sure it has been
installed.
-- Configuring incomplete, errors occurred!
The problem is that I have searched and I don't have a FindCaffe.cmake file on my computer. I found an example for CaffeConfig.cmake, but I tried it and it doesn't work either.
Is there a way I can link Caffe with my C++ project? Thanks!
To fix this issue you may do the following:
Download this FindCAFFE.cmake file
Create cmake dir in your repo root directory and put the downloaded file there.
Modify your CMake file:
add set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${PROJECT_SOURCE_DIR}/cmake")
change set (Caffe_DIR "/home/tamas/caffe") to set (CAFFE_ROOT_DIR "/home/tamas/caffe")
change find_package(Caffe REQUIRED) to find_package(CAFFE REQUIRED)
use CAFFE_INCLUDE_DIRS and CAFFE_LIBRARIES for include directories and link libraries respectively
Clean up your build dir and run cmake command again
<library>_DIR should not be set manually in CMake code usually. There are better alternatives that should be used as setting these variable won't necessarily do what you want. It won't change where find_package finds its libraries.
The CaffeConfig.cmake file is generated when building Caffe. You should never download another one, these files are compatible only with a specific build configuration.
The Caffe library supports to be used with CMake, so FindCaffe.cmake is unnecessary.
For find_package to work, either set the <package>_ROOT variable (require CMake 3.12 minimum) or you must append the install path in CMAKE_PREFIX_PATH. Here's a CMake example that uses the prefix path:
# If you only built the library
list (APPEND CMAKE_PREFIX_PATH "/home/tamas/caffe/build-dir")
# If you installed the library there
list (APPEND CMAKE_PREFIX_PATH "/home/tamas/caffe/")
find_package(Caffe REQUIRED)
Note that the Caffe_LIBRARIES and Caffe_INCLUDE_DIRS won't be set. This is old CMake style and the Caffe library uses the new style. This is what you should do:
target_link_libraries(main PUBLIC caffe caffeproto)
This line add both include directory and adds linking to the libraries too.

what is the proper way of configuring visual studio code to use sdl2 over mingw32 and cmake [duplicate]

I'm trying to use CLion to create a SDL2 project.
The problem is that the SDL headers can't be found when using #include's.
My CMakeLists.txt file:
cmake_minimum_required(VERSION 2.8.4)
project(ChickenShooter)
set(SDL2_INCLUDE_DIR C:/SDL/SDL2-2.0.3/include)
set(SDL2_LIBRARY C:/SDL/SDL2-2.0.3/lib/x64)
include_directories(${SDL2_INCLUDE_DIR})
set(SOURCE_FILES main.cpp)
add_executable(ChickenShooter ${SOURCE_FILES})
target_link_libraries(ChickenShooter ${SDL2_LIBRARY})
My test main.cpp:
#include <iostream>
#include "SDL.h" /* This one can't be found */
int main(){
if (SDL_Init(SDL_INIT_VIDEO) != 0){
std::cout << "SDL_Init Error: " << SDL_GetError() << std::endl;
return 1;
}
SDL_Quit();
return 0;
}
Thank you for any help you could give me.
Edit:
I'm using Windows and CLion is configured to use cygwin64.
This blog post shows how you can do it: Using SDL2 with CMake
On Linux you can use a recent CMake (e.g. version 3.7) and using SDL2 works out of the box.
cmake_minimum_required(VERSION 3.7)
project(SDL2Test)
find_package(SDL2 REQUIRED)
include_directories(SDL2Test ${SDL2_INCLUDE_DIRS})
add_executable(SDL2Test Main.cpp)
target_link_libraries(SDL2Test ${SDL2_LIBRARIES})
Under Windows you can download the SDL2 development package, extract it somewhere and then create a sdl-config.cmake file in the extracted location with the following content:
set(SDL2_INCLUDE_DIRS "${CMAKE_CURRENT_LIST_DIR}/include")
# Support both 32 and 64 bit builds
if (${CMAKE_SIZEOF_VOID_P} MATCHES 8)
set(SDL2_LIBRARIES "${CMAKE_CURRENT_LIST_DIR}/lib/x64/SDL2.lib;${CMAKE_CURRENT_LIST_DIR}/lib/x64/SDL2main.lib")
else ()
set(SDL2_LIBRARIES "${CMAKE_CURRENT_LIST_DIR}/lib/x86/SDL2.lib;${CMAKE_CURRENT_LIST_DIR}/lib/x86/SDL2main.lib")
endif ()
string(STRIP "${SDL2_LIBRARIES}" SDL2_LIBRARIES)
When you now configure inside the CMake-GUI application there will be a SDL2_DIR variable. You have to point it to the SDL2 directory where you extracted the dev package and reconfigure then everything should work.
You can then include SDL2 headers by just writing #include "SDL.h".
Don't set the path to SDL2 by hand. Use the proper find command which uses FindSDL. Should look like:
find_file(SDL2_INCLUDE_DIR NAME SDL.h HINTS SDL2)
find_library(SDL2_LIBRARY NAME SDL2)
add_executable(ChickenShooter main.cpp)
target_include_directories(ChickenShooter ${SDL2_INCLUDE_DIR})
target_link_libraries(ChickenShooter ${SDL2_LIBRARY})
If SDL2 is not found, you have to add the path to SDL2 to CMAKE_PREFIX_PATH, that's the place where CMake looks for installed software.
If you can use Pkg-config, its use might be easier, see How to use SDL2 and SDL_image with cmake
If you feel more comfortable to use a FindSDL2.cmake file similar to FindSDL.cmake provided by CMake, see https://brendanwhitfield.wordpress.com/2015/02/26/using-cmake-with-sdl2/
You can also pull in the SDL source repository as a submodule and build/link it statically along with your main program via add_subdirectory() and target_link_libraries():
cmake_minimum_required( VERSION 3.18.0 )
project( sdl2-demo )
set( SDL_STATIC ON CACHE BOOL "" FORCE )
set( SDL_SHARED OFF CACHE BOOL "" FORCE )
# 'external/sdl' should point at a SDL
# repo clone or extracted release tarball
add_subdirectory( external/sdl )
add_executable(
${CMAKE_PROJECT_NAME}
"src/main.cpp"
)
target_link_libraries( ${CMAKE_PROJECT_NAME} SDL2main SDL2-static )
(At least as of the release-2.0.9 tag, possibly earlier.)
I recently discovered the latest version of SDL2 (version 2.0.12) now comes with all the required CMake config/install scripts, so there's no need to use FindSDL anymore.
I downloaded the SDL source from https://www.libsdl.org/download-2.0.php then from the root folder ran...
cmake -S . -B build/debug -G Ninja -DCMAKE_INSTALL_PREFIX=./install -DCMAKE_BUILD_TYPE=Debug
cmake --build build/debug --target install
This will build and install the debug version of the library, you can then also run...
cmake -S . -B build/release -G Ninja -DCMAKE_INSTALL_PREFIX=./install -DCMAKE_BUILD_TYPE=Release
cmake --build build/release --target install
Which will build and install the release version of the library (and because the SDL CMake script uses DEBUG_POSTFIX the release version of the library won't overwrite the debug one as the debug versions all have 'd' appended to their name).
In your CMakeLists.txt file you can then simply do this:
find_package(SDL2 REQUIRED)
add_executable(${PROJECT_NAME} ...)
target_link_libraries(
${PROJECT_NAME} PRIVATE
SDL2::SDL2
SDL2::SDL2main
You'll need to tell your application where to find the SDL install folder if you used a custom location as I've done in the example. To do this from the root folder of your app run:
cmake -S . -B build/debug -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_PREFIX_PATH=</absolute/path/to/install/dir>
cmake --build build/debug
Note: You can use $(pwd) (*nix/macOS) or %cd% (Windows) to create a hybrid relative path which can be very useful.
You can omit both DCMAKE_INSTALL_PREFIX and DCMAKE_PREFIX_PATH if you want to install SDL to the default system location.
In the examples I've opted to use the Ninja generator as it is consistent across macOS/Windows - it can be used with MSVC/Visual Studio, just make sure you run this (path may differ slightly depending on year/version) to add Ninja to your path.
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat
Update:
One other thing I remembered which is useful on Windows is the ability to copy the SDL .dll file into the application binary directory, this can be achieved like so:
if (WIN32)
# copy the .dll file to the same folder as the executable
add_custom_command(
TARGET ${PROJECT_NAME} POST_BUILD
COMMAND ${CMAKE_COMMAND} -E copy_if_different
$<TARGET_FILE:SDL2::SDL2>
$<TARGET_FILE_DIR:${PROJECT_NAME}>
VERBATIM)
endif()
Using the SDL2 CMake module that I developed, you can integrate the SDL2 library easily in a modern and portable approach.
You should just copy the module in cmake/sdl2 (Or just clone the modules repo) in your project:
git clone https://github.com/aminosbh/sdl2-cmake-modules cmake/sdl2
Then add the following lines in your CMakeLists.txt:
list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/sdl2)
find_package(SDL2 REQUIRED)
target_link_libraries(${PROJECT_NAME} SDL2::Main)
Note: If CMake didn't find the SDL2 library (in Windows), we can specify the CMake option SDL2_PATH as follows:
cmake .. -DSDL2_PATH="/path/to/sdl2"
For more details, please read the README.md file.
The SDL2 CMake modules support other related libraries : SDL2_image, SDL2_ttf, SDL2_mixer, SDL2_net and SDL2_gfx.
You can find a list of examples/samples and projects that uses these modules here : https://github.com/aminosbh/sdl-samples-and-projects
With the compiled version of SDL2-2.0.9 with MinGW-w64 in Windows, the following configuration works for me:
find_package(SDL2 REQUIRED)
add_executable(sdl-test ${SOURCES})
target_link_libraries(sdl-test
mingw32
SDL2::SDL2main
SDL2::SDL2
)
A longer explanation
By reading SDL2Targets.cmake file, I've learned that SDL2 is providing several targets:
SDL2::SDL2main (lib/libSDL2main.a)
SDL2::SDL2 (lib/libSDL2.dll.a)
SDL2::SDL2-static (lib/libSDL2-static.a)
Each of them has INTERFACE_INCLUDE_DIRECTORIES defined, which means we don't need to manually specify include_directories for SDL2.
But by only adding SDL2::SDL2main and SDL2::SDL2 as target_link_libraries is not enough. The g++ compiler might be complaining about "undefined reference to `WinMain'".
By inspecting the compiler options, I found that the SDL2 libraries are added before -lmingw32 option. In order to make the -lmingw32 option comes before SDL2 libraries, we have to also specify mingw32 as the first target_link_libraries. Which will make this configuration working.
The command that I have used for building it is:
$ mkdir build && cd build && cmake .. -G"MinGW Makefiles" && cmake --build .
The only small problem here is in the finally generated compiler options, the -lmingw32 option is duplicated. But since it doesn't affect the linking process, I've ignored it for now.
On Linux, in Clion, this works:
cmake_minimum_required(VERSION 3.20)
project(first_game)
set(CMAKE_CXX_STANDARD 14)
find_package(SDL2 REQUIRED)
include_directories(${SDL2_INCLUDE_DIRS})
add_executable(${PROJECT_NAME} main.cpp)
target_link_libraries(${PROJECT_NAME} ${SDL2_LIBRARIES})
You don't seems to have a CMake error whike generating your make file. But I think your problem is, the SDL Header are located in a subfolder named "SDL2".
Change your CMakeLists.txt to include
C:/SDL/SDL2-2.0.3/include/SDL2
Instead of
C:/SDL/SDL2-2.0.3/include
I had the same problem and none of the other solutions worked.
But I finally got it working by following this solution : How to properly link libraries with cmake?
In a nutshell, the problem was that the SDL2 library was not linked properly in my CMakeLists.txt. And by writing this into the file, it worked (more explainations in the other thread) :
project (MyProgramExecBlaBla) #not sure whether this should be the same name of the executable, but I always see that "convention"
cmake_minimum_required(VERSION 2.8)
ADD_LIBRARY(LibsModule
file1.cpp
file2.cpp
)
target_link_libraries(LibsModule -lpthread)
target_link_libraries(LibsModule liblapack.a)
target_link_libraries(LibsModule -L/home/user/libs/somelibpath/)
ADD_EXECUTABLE(MyProgramExecBlaBla main.cpp)
target_link_libraries(MyProgramExecBlaBla LibsModule)
Highlighting the steps of how I was able to eventually accomplish this using the FindSDL2.cmake module:
Download SDL2-devel-2.0.9-VC.zip (or whatever version is out after this answer is posted) under the Development Libraries section of the downloads page.
Extract the zip folder and you should see a folder similar to "SDL2-2.0.9". Paste this folder in your C:\Program Files(x86)\ directory.
Copy the FindSDL2.cmake module and place it in a new "cmake" directory within your project. I found a FindSDL2.cmake file in the answer referenced in the Accepted Answer: https://brendanwhitfield.wordpress.com/2015/02/26/using-cmake-with-sdl2/
Find the SET(SDL2_SEARCH_PATHS line in the FindSDL2.cmake and add your copied development directory for SDL2 as a new line: "/Program Files (x86)/SDL2-2.0.9" # Windows
Within my CMakeLists.txt, add this line: set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
After this, running CMake worked for me. I'm including the rest of my CMakeLists just in case it further clarifies anything I may have left out:
cmake_minimum_required(VERSION 2.8.4)
project(Test_Project)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
# includes cmake/FindSDL2.cmake
set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
set(SOURCE_FILES src/main.cpp src/test.cpp)
add_executable(test ${SOURCE_FILES})
# The two lines below have been removed to run on my Windows machine
#INCLUDE(FindPkgConfig)
#PKG_SEARCH_MODULE(SDL2 REQUIRED sdl2)
find_package(SDL2 REQUIRED)
INCLUDE_DIRECTORIES(${SDL2_INCLUDE_DIR})
TARGET_LINK_LIBRARIES(chip8 ${SDL2_LIBRARY})
Hope this helps somebody in the near future.
by the time of my answer, SDL2 is provided with sdl2-config executable (as I understand, developers call him "experimental").
After "make install" of SDL2 you can try calling it from terminal with
sdl2-config --cflags --libs to see what it outputs.
And then you can add call to it in your makefile:
set(PROJECT_NAME SomeProject)
project(${PROJECT_NAME})
execute_process(COMMAND /usr/local/bin/sdl2-config --libs RESULT_VARIABLE CMD_RES OUTPUT_VARIABLE SDL2_CFLAGS_LIBS ERROR_VARIABLE ERR_VAR OUTPUT_STRIP_TRAILING_WHITESPACE)
message("SDL2_CFLAGS_LIBS=${SDL2_CFLAGS_LIBS}; CMD_RES=${CMD_RES}; ERR_VAR=${ERR_VAR}")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 ${SDL2_CFLAGS_LIBS}")
set(SOURCE_FILES main.cpp)
add_executable(${PROJECT_NAME} ${SOURCE_FILES})
Here I have a problem - if I only put an executable name without path like
execute_process(COMMAND sdl2-config --libs <...>
I get error "No such file", i.e. cmake does not search in current path and I don't know how to write it properly by now.
One more notice: in my makefile I do not user --cflags option, because cmake finds includes correctly and I do not need to specify them explicitly.
For your information, I was able to successfully cmake and compile SDL2_ttf while linking to SDL2 source code.
At first I was getting errors due to cmake not being able to locate SDL2, even though it was specified in cmake using the SLD2_DIR variable in cmake.
It seems that for some reason cmaking SDL2 fails to create the SDL2Targets.cmake file which is searched for by SDL2_ttf
If this is the case for you, get the SDL2Targets.cmake file from https://bugs.archlinux.org/task/57972 and modify the file like so:
You can remove the following lines:
get_filename_component(_IMPORT_PREFIX "${CMAKE_CURRENT_LIST_FILE}" PATH)
get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
if(_IMPORT_PREFIX STREQUAL "/")
set(_IMPORT_PREFIX "")
endif()
and add this one:
set(_IMPORT_PREFIX "C:/SDL2-2.0.12")
Obviously change the filepath to the place you unpacked the SDL2 source code
I'm not sure if this is exactly your issue, but there it is.

CMAKE: How do I install executable along with required dylib to custom directory?

So I'm using CMake to build a C++ project (on Mac OS) and my project relies on a dylib (I'm using TBB https://www.threadingbuildingblocks.org/ but the specific library itself doesn't matter)
If I do a standard "cmake" and "make" it builds the executable where I want it and when I run my app, the dylib links correctly and everything works perfectly.
The problem comes in when I try to do a "make install" and try to run the resulting executable from the install directory. I get an "image not found" error:
dyld: Library not loaded: #rpath/libtbb.dylib
Referenced from:
/Users/MyName/Desktop/ProjectRoot/install/./MyApp
Reason: image not found
Interestingly, if I do a regular "make" without an install, and then manually copy over the executable to the install directory, then that will link against my dylib properly. I have no idea why that is.
My directory structure is as follows:
Root
CMakeLists.txt
Source/
Libraries/
tbb/
include/
lib/
libtbb.dylib
install/
...and my CMakeLists.txt file is below:
# Start of CMakeLists.txt
cmake_minimum_required(VERSION 3.3)
project (MyApp)
# Set C++ version and output paths
set (CMAKE_CXX_STANDARD 14)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR})
set(CMAKE_MACOSX_RPATH 1)
set(CMAKE_INSTALL_PREFIX "${CMAKE_SOURCE_DIR}/install")
set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib")
# Find TBB
find_library (
TBB_LIBRARIES
NAMES tbb libtbb # what to look for
HINTS "${CMAKE_SOURCE_DIR}/Libraries/tbb/lib" # where to look
NO_DEFAULT_PATH # do not search system default paths
)
# Set Custom Include Files + TBB header files
include_directories(Source/Headers Libraries/tbb/include)
# Set Source Files
file(GLOB_RECURSE SRC_FILES "Source/*.cpp")
add_executable(MyApp ${SRC_FILES})
# Link Libraries
target_link_libraries(MyApp ${TBB_LIBRARIES})
# Set compile flags
set_target_properties(MyApp PROPERTIES CXX_STANDARD 14) #LINK_FLAGS "-Wl")
target_compile_features(MyApp PUBLIC cxx_std_14)
# Install executable
install(TARGETS MyApp DESTINATION .)
If I try to also add the following line, and install the dylib as well:
install(TARGETS ${TBB_LIBRARIES} DESTINATION lib)
then when I do a "make install" I get the following error instead:
install TARGETS given target
"/Users/MyName/Desktop/ProjectRoot/Libraries/tbb/lib/libtbb.dylib"
which does not exist in this directory.
So I just can't seem to get this install to work. How do I fix it so that both my executable and my library get installed in the right place and that my executable will be able to link against my library when run?

GTest build first at CMake [duplicate]

This question already has answers here:
How to start working with GTest and CMake
(11 answers)
Closed 6 years ago.
I'm building dynamic library and want to use gtest for testing.
SET(GTEST_LIBRARY libs/googletest-master)
set(GTEST_INCLUDE_DIR libs/googletest-master/googletest/include)
#set(GTEST_MAIN_LIBRARY libs/googletest-master/googletest/include/gtest)
#find_package(PostgreSQL REQUIRED)
enable_testing()
find_package(GTest REQUIRED)
include_directories(${GTEST_INCLUDE_DIR})
But, berofe setting GTEST_MAIN_LIBRARY I have to build it first.
How I can configure CMake to achieve this
Build gtest with Cmake && make (on unix)
Get appropriate path to GTEST_MAIN_LIBRARY
continue build
I copied gtests srcs into project
make a build with Make
and add this to CMake
add_subdirectory(libs/googletest-master)
SET(GTEST_LIBRARY libs/googletest-master)
set(GTEST_INCLUDE_DIR libs/googletest-master/googletest/include)
set(GTEST_MAIN_LIBRARY libs/googletest-master/googlemock/gtest)
enable_testing()
find_package(GTest REQUIRED)
include_directories(${GTEST_INCLUDE_DIR})
include_directories(${gtest_SOURCE_DIR}/include ${gtest_SOURCE_DIR})
If your put the source for googletest in a subdirectory parented where your CMakeLists.txt file is, the following should work:
add_subdirectory(./googletest)
add_executable(your_program ${MY_SRC})
add_dependencies(your_program gmock)
add_dependencies(your_program gtest)

Check where include/library path variables like OpenCV_LIBS point to in unix

When using some libraries like OpenCV with C/C++, variables like OpenCV_LIBS are used to point the compiler/linker to the relevant directories.
Examples using cmake:
include_directories( ${OpenCV_INCLUDE_DIRS} )
target_link_libraries( project_name ${OpenCV_LIBS} )
How can I check where such variables point at? I've tried typing set or printenv in terminal but it shows only some system variables. Also how can I set/change such variables?
Those variables are determined by cmake (see OpenCVConfig.cmake for a more detailed description of opencv CMake variables available).
To see those values you can add message() calls after the find_package(OpenCV) call to your project's CMakeLists.txt:
find_package(OpenCV)
message(STATUS "OpenCV_INCLUDE_DIRS = ${OpenCV_INCLUDE_DIRS}")
message(STATUS "OpenCV_LIBS = ${OpenCV_LIBS}")
Alternatively you can run find_package via a CMake command line option.
Here are a few examples (the CMAKE_PREFIX_PATH part is optional if CMake is not able to find your libraries installation path automatically):
MODE=COMPILE giving include directories (e.g. with MSVC compiler)
$ cmake
--find-package
-DNAME=OpenCV
-DCOMPILER_ID=MSVC -DMSVC_VERSION=1700
-DLANGUAGE=CXX
-DMODE=COMPILE
-DCMAKE_PREFIX_PATH:PATH=/path/to/your/OpenCV/build
MODE=LINK giving link libraries (e.g. with GNU compiler)
$ cmake
--find-package
-DNAME=OpenCV
-DCOMPILER_ID=GNU
-DLANGUAGE=CXX
-DMODE=LINK
-DCMAKE_PREFIX_PATH:PATH=/path/to/your/OpenCV/build
Note: This CMake call will create a CMakeFiles sub-directory in your current working directory.
References
Using OpenCV with gcc and CMake
CMakeFindPackageMode CMake module documentation