I want to build an application that depends on the OpenCV (version 3.4.6) viz module. This module has the VTK library (version 7.1.1) as dependency. I want to use ExternalProject to build both, the vtk library and the opencv viz module and subsequently want to build the main application, all in one cmake run.
.
├── CMakeLists.txt
├── deps
│ └── CMakeLists.txt
└── main.cpp
I am using the cmake ExternalProject module to build both opencv and vtk inside a subdirectory like this:
deps/CMakeLists.txt
cmake_minimum_required(VERSION 3.14)
project(dependencies)
include(ExternalProject)
ExternalProject_add(
vtklib
GIT_REPOSITORY https://github.com/Kitware/vtk
GIT_TAG v7.1.1
GIT_PROGRESS TRUE
UPDATE_COMMAND ""
CMAKE_ARGS
-DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
-DBUILD_TESTING=OFF
-DBUILD_EXAMPLES=OFF
-DVTK_DATA_EXCLUDE_FROM_ALL=ON
-DVTK_USE_CXX11_FEATURES=ON
-Wno-dev
)
add_library(vtk INTERFACE IMPORTED GLOBAL)
add_dependencies(vtk vtklib)
ExternalProject_add(
ocv
GIT_REPOSITORY https://github.com/opencv/opencv
GIT_TAG 3.4.6
GIT_PROGRESS TRUE
UPDATE_COMMAND ""
CMAKE_ARGS
-DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
-DWITH_VTK=ON
-Wno-dev
)
# ExternalProject_Get_Property(ocv install_dir)
# include_directories(${install_dir}/src/ocv/include)
include_directories(${CMAKE_INSTALL_PREFIX}/include)
set(ocv_libdir ${CMAKE_INSTALL_PREFIX}/${CMAKE_VS_PLATFORM_NAME}/vc15)
set(OCV_VERSION 346)
add_dependencies(ocv vtklib)
add_library(opencv_core SHARED IMPORTED)
set_target_properties(opencv_core PROPERTIES
IMPORTED_IMPLIB "${ocv_libdir}/lib/opencv_core${OCV_VERSION}.lib"
IMPORTED_LOCATION "${ocv_libdir}/bin/opencv_core${OCV_VERSION}.dll"
)
add_library(opencv_viz SHARED IMPORTED)
set_target_properties(opencv_viz PROPERTIES
IMPORTED_IMPLIB "${ocv_libdir}/lib/opencv_viz${OCV_VERSION}.lib"
IMPORTED_LOCATION "${ocv_libdir}/bin/opencv_viz${OCV_VERSION}.dll"
)
the main CMakeLists.txt looks like this:
cmake_minimum_required(VERSION 3.14)
project(cmaketest VERSION 0.1 DESCRIPTION "" LANGUAGES CXX)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_Flags "${CMAKE_CXX_FLAGS} -std=c++17")
# include_directories(${CMAKE_INSTALL_PREFIX}/include)
add_subdirectory(deps)
add_executable(${PROJECT_NAME} main.cpp)
target_link_libraries(${PROJECT_NAME} opencv_core opencv_viz)
install(
TARGETS ${PROJECT_NAME}
EXPORT "${PROJECT_NAME}-targets"
LIBRARY DESTINATION lib/
ARCHIVE DESTINATION lib/${CMAKE_PROJECT_NAME}
RUNTIME DESTINATION bin
PUBLIC_HEADER DESTINATION include/${CMAKE_PROJECT_NAME}/${PROJECT_NAME}
)
the main.cpp for completeness:
#include <opencv2/viz.hpp>
int main(){}
but it seems that the include_directories and add_library calls inside deps/CMakeLists.txt do not work on the correct scope as i am getting the following error messages:
error C1083: File (Include) can not be opened: "opencv2/viz.hpp"
if i uncomment the include_directories inside the main CMakeLists.txt then i get a linker error (this is not what i want, included directories should be specified inside deps/CMakeLists.txt):
LNK1181: opencv_core.lib can not be opened
If i just copy the contents of deps/CMakeLists.txt in the main CMakeLists.txt in place of the add_subdirectory call everything works fine.
So, how do i get the include directories and the created targets from the subdirectory in my main CMakeLists?
edit:
call to cmake configure:
cmake.exe -B build -S . -G "Visual Studio 17 2022" -A x64 -T v141 -DCMAKE_INSTALL_PREFIX=D:/test
call to cmake build:
cmake.exe --build build --config Release --target install
Unlike to normal targets, which are global, an IMPORTED target by default is local to the directory where it is created.
For extend visibility of the IMPORTED target, use GLOBAL keyword:
add_library(opencv_core SHARED IMPORTED GLOBAL)
This is written in the documentation for add_library(IMPORTED):
The target name has scope in the directory in which it is created and below, but the GLOBAL option extends visibility.
cmake has couple steps:
configuration
generation (depends on configuration)
build (depends on generation)
test (depends on build)
install (depends on build)
Now problem is that your build step depends on result of install step. This happens here:
set(ocv_libdir ${CMAKE_INSTALL_PREFIX}/${CMAKE_VS_PLATFORM_NAME}/vc15)
and when this variable is used.
This is causing that to be able to complete build step you need success in install step. And cmake will do install step after successful build. So you have dependency cycle.
Instead importing opencv as shared library:
add_library(opencv_viz SHARED IMPORTED)
Link your target with targets created by imported project of opnecv.
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.
I am working inside a container. I want to try gtest so first I installed it by doing this inside the container:
Download the source file from github/google/googletest
build the project by cmake CMakeLists.txt
call make
cd lib and cp * /usr/lib
cd googlemock/include and cp -r gmock /usr/local/include
cd googletest/include and cp -r gtest /usr/local/include
After this I created a CMakeLists.txt file as
cmake_minimum_required(VERSION 3.13)
set(CMAKE_CXX_STANDARD 11)
find_package(GTest REQUIRED)
message("GTest_INCLUDE_DIRS = ${GTest_INCLUDE_DIRS}")
add_executable(myExecutable main.cpp)
target_link_libraries(myExecutable ${GTEST_LIBRARIES} pthread)
With this, I could use gtest without problem. (main.cpp contained some tests)
Then I want to do the same for a ROS project I have, so after creating a workspace and a package that depends on gtest I did catkin_make and I get
- +++ processing catkin package: 'ros_gtest'
-- ==> add_subdirectory(ros_gtest)
-- Could NOT find GTest (missing: GTest_DIR)
-- Could not find the required component 'GTest'. The following CMake error indicates that you either need to install the package with the same name or change your environment so that it can be found.
CMake Error at /opt/ros/noetic/share/catkin/cmake/catkinConfig.cmake:83 (find_package):
Could not find a package configuration file provided by "GTest" with any of
the following names:
GTestConfig.cmake
gtest-config.cmake
Add the installation prefix of "GTest" to CMAKE_PREFIX_PATH or set
"GTest_DIR" to a directory containing one of the above files. If "GTest"
provides a separate development package or SDK, be sure it has been
installed.
Call Stack (most recent call first):
ros_gtest/CMakeLists.txt:10 (find_package)
-- Configuring incomplete, errors occurred!
See also "/root/ros_gtest_example/build/CMakeFiles/CMakeOutput.log".
See also "/root/ros_gtest_example/build/CMakeFiles/CMakeError.log".
make: *** [Makefile:320: cmake_check_build_system] Error 1
In this case the CMakeLists.txt start as
cmake_minimum_required(VERSION 3.0.2)
project(ros_gtest)
## Compile as C++11, supported in ROS Kinetic and newer
# add_compile_options(-std=c++11)
## Find catkin macros and libraries
## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)
## is used, also find other catkin packages
find_package(catkin REQUIRED COMPONENTS
GTest
roscpp
rospy
std_msgs
)
I wonder why it does not work in this case but it works in the other?
missing make install and you don't copy any gtest config file...
IMHO, You should use FetchContent() or/and learn how CMake find_package() work...
include(CTest)
if(BUILD_TESTING)
include(FetchContent)
FetchContent_Declare(
googletest
GIT_REPOSITORY https://github.com/google/googletest.git
GIT_TAG master)
set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
FetchContent_MakeAvailable(googletest)
endif()
ref: mizux/cmake-cpp
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.
I am not a C++ programmer, only have made a course a while ago. Using homebrew I installed libbitcoin and was hoping that I can reference the library like I was able to reference the boost libraries. I also realized that there are no links in /usr/local/bin to the Cellar.
I think I could get it working by using the absolute paths but I am looking for the proper way of handling this constellation that I just mentioned.
Current CMake:
cmake_minimum_required(VERSION 2.8.4)
project(cplusplus)
message(STATUS "start running cmake...")
find_package(boost 1.65.1 COMPONENTS system filesystem REQUIRED)
find_package(libbitcoin 3.3.0 COMPONENTS system filesystem REQUIRED)
message("system: ${CMAKE_SYSTEM_PREFIX_PATH}")
find_library(LIB_BITCOIN libbitcoin)
message("bitcoin: ${LIB_BITCOIN}")
if(Boost_FOUND)
message(STATUS "Boost_INCLUDE_DIRS: ${Boost_INCLUDE_DIRS}")
message(STATUS "Boost_LIBRARIES: ${Boost_LIBRARIES}")
message(STATUS "Boost_VERSION: ${Boost_VERSION}")
include_directories(${Boost_INCLUDE_DIRS})
endif()
add_executable(cplusplus main.cpp)
if(Boost_FOUND)
target_link_libraries(cplusplus ${Boost_LIBRARIES})
endif()
Currently I get these errors:
/Applications/CLion.app/Contents/bin/cmake/bin/cmake -DCMAKE_BUILD_TYPE=Debug -G "CodeBlocks - Unix Makefiles" /Users/johndow/Documents/Workspace/bitcoin-code/cplusplus
-- start running cmake...
-- Boost version: 1.65.1
CMake Error at CMakeLists.txt:8 (find_package):
By not providing "Findlibbitcoin.cmake" in CMAKE_MODULE_PATH this project
has asked CMake to find a package configuration file provided by
"libbitcoin", but CMake did not find one.
Could not find a package configuration file provided by "libbitcoin"
(requested version 3.3.0) with any of the following names:
libbitcoinConfig.cmake
libbitcoin-config.cmake
Add the installation prefix of "libbitcoin" to CMAKE_PREFIX_PATH or set
"libbitcoin_DIR" to a directory containing one of the above files. If
"libbitcoin" provides a separate development package or SDK, be sure it has
been installed.
-- Configuring incomplete, errors occurred!
See also "/Users/johndoe/Documents/Workspace/bitcoin-code/cplusplus/cmake-build-debug/CMakeFiles/CMakeOutput.log".
[Finished]
You seem to have double lookup for libbitcoin library in your CMakeLists file. You are first looking for it by:
find_package(libbitcoin ...)
and then by
find_library(LIB_BITCOIN libbitcoin)
Cmake is not happy (as your error message says) with the find_package() clause as libbitcoin does not provide cmake configuration by itself. You have many ways how to fix it, just two of them:
remove find_package() and use only find_library(), I think this is the simpler way and your project should work this way
provide cmake configuration for libbitcoin by yourself. Good introduction how to do this is here (and good to read anyway):
https://cmake.org/Wiki/CMake:How_To_Find_Libraries
As far as I know, currently libbitcoin does not export any <libbitcoin>Config.cmake package.
But it does export a libbitcoin.pc file for generic use with pkg-config.
ie: /usr/local/lib/pkgconfig/libbitcoin.pc
If you get results from invoking pkg-config --cflags libbitcoin then it's there.
And then you can put something like this in your CMakeLists.txt:
#use this if libbitcoin is installed to some custom location
set(ENV{PKG_CONFIG_PATH} "/path/to/libbitcoin/pkgconfig/:$ENV{PKG_CONFIG_PATH}")
#then later..
find_package(PkgConfig REQUIRED)
pkg_check_modules(LIB_BITCOIN REQUIRED libbitcoin)
#then later..
target_link_libraries(${PROJECT_NAME} PRIVATE ${LIB_BITCOIN_LIBRARIES})
target_include_directories(${PROJECT_NAME} PRIVATE ${LIB_BITCOIN_INCLUDE_DIRS})
That should pull in boost, make the libbitcoin includes visible and solve all manner of compiler and linker woes.
(Or if you are feeling mad, you could always make use of this gist).