My computer has multiple versions of the eigen library. I have an eigen3 in the /usr/include/ and another eigen3 in the /usr/local/. I use the set() command in cmakelists, but the compiler only uses the eigen library in the/usr/include directory. Here are my cmakelists.txt settings
`
cmake_minimum_required(VERSION 2.8.3)
project(cmake_test)
set(EIGEN3_DIR "/usr/local/eigen-3.3.9/share/eigen3/cmake/")
find_package(Eigen3)
include_directories(
# "/usr/local/eigen-3.3.9/include/eigen3/"
${PROJECT_SOURCE_DIR}/include
${EIGEN3_INCLUDE_DIR}
)
message("EIGEN3_INCLUDE_DIR =======" ${EIGEN3_DIR})
message("EIGEN3_INCLUDE_DIR =======" ${EIGEN3_INCLUDE_DIR})
add_executable(cmake_test src/main.cpp)
`
Does anyone know where I went wrong
I hope someone can tell me how cmake searches for header files, library files, and Search order of the find_ package() command
Related
I build llvm from git and want to use the libraries in a project, especially the libclang.
The "makefiles" are generated by means of CMake and for the LLVM part I found the setting LLVM_DIR to reroute the path for the llvm libraries, but for Clang I cannot find such a variable and I still see in my link line (it is a Cygwin system):
/usr/lib/libclang.dll.a /usr/lib/libclangTooling.dll.a.
Question: which environment variable do I set to get the right build Clang libraries?
The variable is Clang_DIR.
Just in case, I attach a minimalistic example of CMakeLists.txt file as well.
cmake_minimum_required(VERSION 3.12)
# Find CMake file for Clang
find_package(Clang REQUIRED)
# Add path to LLVM modules
set(CMAKE_MODULE_PATH
${CMAKE_MODULE_PATH}
"${LLVM_CMAKE_DIR}"
)
# import LLVM CMake functions
include(AddLLVM)
include_directories(${LLVM_INCLUDE_DIRS})
include_directories(${CLANG_INCLUDE_DIRS})
add_definitions(${LLVM_DEFINITIONS})
add_definitions(${CLANG_DEFINITIONS})
add_llvm_executable(myTool main.cpp)
set_property(TARGET myTool PROPERTY CXX_STANDARD 11)
target_link_libraries(myTool PRIVATE clangTooling)
I am trying to link my local version of gflags (which is in ~/mylibs/gflags) while compiling google-test. In gtest's CMakeLists.txt, it's using find_package:
if (WITH_GFLAGS)
find_package (gflags 2.2.0)
if (gflags_FOUND)
set (HAVE_LIB_GFLAGS 1)
determine_gflags_namespace (gflags_NAMESPACE)
endif (gflags_FOUND)
endif (WITH_GFLAGS)
I don't want to modify the CMakeLists.txt file. Is there anyway to tell cmake to find the package in my folder ?
Thanks!
The gflags documentation describes specifying the location of a non-standard installation when using CMake:
The gflags_DIR variable must be set to the <prefix>/lib/cmake/gflags directory containing the gflags-config.cmake file
In your case, this might look like:
cmake -Dgflags_DIR=/home/blackball/mylibs/gflags/lib/cmake/gflags [...]
Since you are integrating gflags as subproject in a super cmake, you basically want find_package() to be a no-op if you have it in your "meta-project" source dir. This can be done by overloading the find_package() command.
Top CMakeLists.txt:
# Use find_package everywhere, no-op if it's a subproject
macro(find_package)
if(NOT TARGET ${ARGV0} AND NOT TARGET ${ARGV0}::${ARGV0})
_find_package(${ARGV})
else()
if(TARGET ${ARGV0})
get_target_property(TGT_VER ${ARGV0} VERSION)
set(TGT ${ARGV0})
else()
get_target_property(TGT_VER ${ARGV0}::${ARGV0} VERSION)
set(TGT ${ARGV0}::${ARGV0})
endif()
message(STATUS "Found ${ARGV0}: CMake Target ${TGT} (found version \"${TGT_VER}\")")
set(${ARGV0}_FOUND TRUE)
endif()
endmacro()
note: for gflags you may need to "force" gflags_NAMESPACE also since gflags it's a source not a binary (cf glog issue ToDo)
I've wanted to use Clion for awhile but I've always had trouble with Cmake. Armed with Cygwin, I've almost gotten this stupid thing to work.
The issue is while I can compile a cmake file from within a cygwin terminal, in Clion I am told it cannot find the library I want.
Error:A required package was not found
The cmakelist.txt file
cmake_minimum_required(VERSION 3.3)
project(Test)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
set(PKG_CONFIG_PATH /usr/lib/pkgconfig)
set(PKG_CONFIG_EXECUTABLE /usr/bin/pkg-config.exe)
set(SOURCE_FILES main.cpp)
add_executable(Test ${SOURCE_FILES})
INCLUDE(FindPkgConfig)
pkg_check_modules(SDL2 REQUIRED "sdl2")
MESSAGE(STATUS "SDL library: " ${SDL2_LDFLAGS})
TARGET_LINK_LIBRARIES(Test ${SDL2_LDFLAGS})
I have no idea if setting the variables PKG_CONFIG_PATH and others work, but they successfully build a makefile for my use in cygwin that builds correctly.
I've deleted the cache, remade the project and everything. It just refuses to work in Clion
If I understood correctly, your cmake config is unable to find SDL library. I found it better to use find_package command instead of pkg_check_modules.
In order to find_package(SDL2) to work, there must be FindSDL2.cmake module in directory, specified by CMAKE_MODULE_PATH variable (usually, it is cmake/Modules directory inside your source tree).
FindSDL2.cmake is not a part of CMake, but you can find one online easily (check my own modules, for example: https://github.com/dragn/cmake-modules).
Refer to this doc for details: https://cmake.org/Wiki/CMake:How_To_Find_Libraries.
Put FindSDL2.cmake to cmake/Modules directory and add this to your CMakeLists.txt:
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_SOURCE_DIR}/cmake/Modules)
find_package(SDL2 REQUIRED)
include_directories(${SDL2_INCLUDE_DIR})
...
target_link_libraries(${PROJECT_NAME} ${SDL2_LIBRARY})
NOTE: Sadly, it appears that Leonardo has not succeeded in finding volunteers for maintaining FindSDL2.cmake in SDL community: https://cmake.org/Bug/view.php?id=14826.
How can you link GLEW to a project with CMake?
We've been trying to link GLEW to our project using CMake for at least 3 hours without any success so any help is accepted.
I'm using the FindGLEW.cmake which comes with CMake 3.1.0
CMakeLists.txt
find_package(GLEW REQUIRED)
if (GLEW_FOUND)
include_directories($(GLEW_INCLUDE_DIRS))
endif()
Environment Variables
I'm using MinGW w64 to compile the sources and we successfully linked GLFW and GLM just by copying the includes and libs to their respective folders, but after doing the same with GLEW, CMake still couldn't find it.
Sorry if I wasn't clear enough while formulating the question. I will provide any additional information required.
Edit: I've managed to link the header files by specifying their location in the CMake Cache file, though I'm getting undefined reference to glew functions like glewInit().
Typical CMake scripts like FindGLEW will define variables that specify the paths and files that your project needs. If the script can't automatically identify the correct paths (usually because of nonstandard install location, which is fine), then it leaves these variables up to you to fill in.
With command line CMake, you use the -D flag to define and set the value of a given variable. Other CMake interfaces, like CMake-gui or an IDE integration, give you this ability some other way.
However you do it, you can also modify the cache directly (CMakeCache.txt) and see what CMake is using in there or just clear the cache altogether. You'll have to rerun CMake for it to pick up your changes.
When it comes to linking, that's when you need to tell CMake which libs to link. Use the link_libraries command with what the automated script gives you.
find_package(GLEW REQUIRED)
include_directories(${GLEW_INCLUDE_DIRS})
link_libraries(${GLEW_LIBRARIES})
Other answers do obviously work, but the target based style of cmake makes it even easier since the GLEW find module defines the imported target GLEW::GLEW. All you need is:
find_package(GLEW REQUIRED)
target_link_libraries(YourTarget GLEW::GLEW)
YourTarget is the target that you created with add_executable or add_library. No need to explicitly add include directories, they are added automatically by linking the targets.
The secret of find_package(GLEW) is in FindGLEW.cmake file with cmake install.
find_path(GLEW_INCLUDE_DIR GL/glew.h)
find_library(GLEW_LIBRARY NAMES GLEW glew32 glew glew32s PATH_SUFFIXES lib64)
The find_path and find_library commands find paths in standard system paths. If you want them to find paths in user defined directories, you should tell them.
For example:
set(CMAKE_PREFIX_PATH "d:/libs/glew-1.10.0")
set(CMAKE_LIBRARY_PATH "d:/libs/glew-1.10.0/lib/Release/Win32/")
find_package(GLEW REQUIRED)
Reference:
http://www.cmake.org/cmake/help/v3.0/command/find_path.html
http://www.cmake.org/cmake/help/v3.0/command/find_library.html
I was struggling hard to link glew to cmake through command line on mac. This might be helpful but I am not sure :) I will walk you through step by step of what I have done.
I installed Cmake source from the web.
Then I went inside the cmake folder in terminal and typed
./bootstrap && make && make install
(this will install cmake command line tools on our OS platform)
I have some exercise files. I want cmake to generate xcode files for me for all those exercise files (ex. triangles.cpp, shader.cpp etc) So i made a directory inside exercise files folder.
$ mkdir xcode
$ cd xcode
$ cmake -G "Xcode" ..
At this point, Cmake suppose to install all xcode files that included correct libraries. But there was an error :
$ cmake -G "Xcode" ..
CMake Warning (dev) at CMakeLists.txt:3 (cmake_minimum_required):
Compatibility with CMake < 2.4 is not supported by CMake >= 3.0.
This warning is for project developers. Use -Wno-dev to suppress it.
system name is: Darwin-14.1.0
system processor is: x86_64
-- Could NOT find GLEW (missing: GLEW_INCLUDE_DIR GLEW_LIBRARY)
-- Could NOT find Doxygen (missing: DOXYGEN_EXECUTABLE)
-- Using Cocoa for window creation
-- Using NSGL for context creation
-- Building GLFW only for the native architecture
CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
Please set them or make sure they are set and tested correctly in the CMake files:
GLEW_LIBRARY
linked by target "TextureLoader" in directory /Users/Mydir/Desktop/Exercise/Exercise Files
-- Configuring incomplete, errors occurred!
Then to make sure I have installed GLEW and all its libraries correctly, I ran
$brew install glew
Yes, I have installed glew already but it was NOT linked. See the Warning below:
Warning: glew-1.12.0 already installed, it's just not linked
Then I ran the following commands:
$ brew unlink glew
$ brew link glew
And I have solved the error. So just make sure that you have linked glew. Hope this helps.
Happy Coding :)
Finally I found a simple and short CMakeLists which works if you have installed everything in default paths.(openGL, glfw and glew)
cmake_minimum_required(VERSION 3.3)
project(openGL_tutorial)
find_package(OpenGL REQUIRED)
if(NOT OPENGL_FOUND)
message("ERROR: OpenGL not found")
endif(NOT OPENGL_FOUND)
set(GL_LIBRARY GL GLU X11)
add_executable(openGL_tutorial main.cpp)
target_link_libraries(openGL_tutorial glfw GLEW libGLEW.so libGLU.so libGL.so)
For what it is worth, in 2023, this works for me, on macOS, with GLEW, GLFW, and CMake installed using Homebrew:
cmake_minimum_required(VERSION 3.10)
project(Project)
add_executable(Project main.cpp)
find_package(glfw3 REQUIRED)
find_package(GLEW REQUIRED)
target_link_libraries(Project glfw GLEW::glew)
CMake cannot find my Eigen3 package. I set an environment variable called
EIGEN3_INCLUDE_DIR
pointing to the path where FindEigen3.cmake is.
Then in the CMakelists.txt I wrote:
find_package( Eigen3 REQUIRED )
include_directories( EIGEN3_INCLUDE_DIR )
I get next message of error:
CMake Error at C:/Program Files (x86)/CMake 2.8/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:91 (MESSAGE):
Could NOT find Eigen3 (missing: EIGEN3_INCLUDE_DIR EIGEN3_VERSION_OK)
(Required is at least version "2.91.0")
Call Stack (most recent call first):
C:/Program Files (x86)/CMake 2.8/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:252 (_FPHSA_FAILURE_MESSAGE)
C:/Program Files (x86)/CMake 2.8/share/cmake-2.8/Modules/FindEigen3.cmake:76 (find_package_handle_standard_args)
test/test_quaternion/CMakeLists.txt:25 (find_package)
Any idea on what I am missing or doing wrong?
Since Eigen3 is completely header only, all you ever need is the path to the include directory. And this one, you are already defining manually anyway. So there is no real need for a FindEigen3.cmake or FIND_PACKAGE call.
Simply use
INCLUDE_DIRECTORIES ( "$ENV{EIGEN3_INCLUDE_DIR}" )
or
SET( EIGEN3_INCLUDE_DIR "$ENV{EIGEN3_INCLUDE_DIR}" )
IF( NOT EIGEN3_INCLUDE_DIR )
MESSAGE( FATAL_ERROR "Please point the environment variable EIGEN3_INCLUDE_DIR to the include directory of your Eigen3 installation.")
ENDIF()
INCLUDE_DIRECTORIES ( "${EIGEN3_INCLUDE_DIR}" )
A few notes:
If you want to access the content of a CMake variable, make sure to use ${...}
$ENV{....} accesses environment variables.
The second example will stop with an error if the environment variable is not set (and, thus, EIGEN3_INCLUDE_DIR cmake variable is empty)
Be careful to use quotation marks around (evaluated) variables if they could contain whitespace. Otherwise, CMake will interpret it as a list.
If you want to use custom find modules, make sure to either place them in you CMake installation or, as #Fraser pointed out above, make sure to point CMAKE_MODULE_PATH to the directory where it is. Not sure, but it could be that CMake checks the current directory as well automatically (where your CMakeLists.txt resides. Anyhow, setting EIGEN3_INCLUDE_DIR is totally unrelated to the location of FindEigen3.cmake
However, it could be that your FindEigen3 script evaluates this variable to determine the location of your Eigen3 installation.
Alternatively, self-built CMake-based projects often provide a <PackageName>Config.cmake. If you point a variable called <PackageName>_DIR to the directory containing this file, you can use FIND_PACKAGE( <PackageName> ...) as normal. See documentation of FIND_PACKAGE for details.
Eigen >= 3.3 has direct CMake integration, so it seems yours isn't set up correctly.
Assume Eigen has been installed to /opt/eigen/3.3 with default settings. Append or prepend the the location /opt/eigen/3.3 to the environment variable CMAKE_PREFIX_PATH e.g in bash:
export CMAKE_PREFIX_PATH="$CMAKE_PREFIX_PATH:/opt/eigen/3.3"
Then CMake should pick it up.
If you are writing your own CMakeLists.txt that uses Eigen I suggest using code like this:
find_package (Eigen3 3.3 REQUIRED)
add_executable (example example.cpp)
target_link_libraries (example Eigen3::Eigen)
You should not use include_directories since CMake 3 was released -- the targets approach should be preferred whenever available.
First, make sure Eigen is properly installed. Refer to the INSTALL file that comes with the tarball.
Second, copy the cmake/FindEigen3.cmake file from the tarball to the directory containing your CMakeLists.txt.
In your CMakeLists.txt add:
set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR})
find_package(Eigen3 REQUIRED)
include_directories(${EIGEN3_INCLUDE_DIR})
Now you should be able to do e.g. #include <Eigen/Core>.
All of this comes (mostly) from this source.
This approach has the advantage over e.g. include_directories("$ENV{EIGEN3_INCLUDE_DIR}") that it the uses CMake's standard mechanism for finding external dependencies, making it easier for someone else (or your future self) to pick up the project, possibly on another platform.
(However, it would be nice if Eigen itself installed an EigenConfig.cmake file, making it accessible through the find_package mechanism without any extra paths.)
I found another solution here (which referred to here) which uses the pkg-config file :
find_package(PkgConfig)
pkg_search_module(Eigen3 REQUIRED eigen3)
As a detailed explanation of the note 7 from the top answer of Johannes. By using the "Config mode" rather than "Module mode" of CMake find_packate(), only writing
find_package( Eigen3 REQUIRED )
include_directories( EIGEN3_INCLUDE_DIR )
in CMakeLists.txt is enough.
Please refer to the INSTALL guidance text file contained in the eigen source code directory (eg. extracted from eigen-3.3.7.tar.gz downloaded from official website), which said:
Method 2. Installing using CMake
********************************
Let's call this directory 'source_dir' (where this INSTALL file is).
Before starting, create another directory which we will call 'build_dir'.
Do:
cd build_dir
cmake source_dir
make install
The "make install" step may require administrator privileges.
You can adjust the installation destination (the "prefix")
by passing the -DCMAKE_INSTALL_PREFIX=myprefix option to cmake, as is
explained in the message that cmake prints at the end.
Just like installing usual CMake projects to your machine.
The difference from directly including the /usr/include/eigne3 or /usr/local/include/eigen3 directory is that, a configuration directory called eigen3/cmake will also be installed to /usr/share or usr/local/share. This configuration directory contains the Eigen3Config.cmake file, which can automatically be found by CMake to locate the eigen3 directory.
If you have not added Eigen Library to environment variable then do the following in CMakeLists.txt:
cmake_minimum_required(VERSION 3.9)
project(ProjectName)
set(CMAKE_CXX_STANDARD 11)
# set EIGEN_DIR variable to Eigen Library Path
set(EIGEN_DIR "C:\\Eigendir\\Eigen")
# include the directory
include_directories(${EIGEN_DIR})
add_executable(ProjectName main.cpp)
target_link_libraries(ProjectName ${EIGEN_DIR})
Another simple way that doesn't require adding an environment variable is to simply find eigen with the cmake find_path function https://cmake.org/cmake/help/v3.6/command/find_path.html. The example code finds the directory "Eigen" in paths "/usr/include/" and "/usr/local/include" with an additional search in subdirectory "eigen3".
find_path(EIGEN3_INCLUDE_DIRS "Eigen" paths "/usr/include" "/usr/local/include" path_suffixes "eigen3")
message(${EIGEN3_INCLUDE_DIRS})
if ( NOT EIGEN3_INCLUDE_DIRS )
message(FATAL_ERROR "CMake variable EIGEN3_INCLUDE_DIRS not found.")
endif()
include_directories ( "${EIGEN3_INCLUDE_DIRS}" )
You could try setting the CMAKE_MODULE_PATH to the location of Eigen subdirectory named "cmake":
cmake . -DCMAKE_MODULE_PATH=<Eigen root dir>/cmake/
I had a similar problem when run cmake .. && make on Google Colab on a project clone from github. I fixed it by editing CMakeLists.txt file and adding this line to it:
set(EIGEN3_INCLUDE_DIR "/usr/include/eigen3")
As you can see, my eigen3 was in /usr/include/eigen3 path (and I had installed it using !sudo apt-get install build-essential cmake libeigen3-dev)
When installing on Kubuntu 20.04 following steps from INSTALL:
Do:
cd build_dir
cmake source_dir
make install
using -DCMAKE_INSTALL_PREFIX=/usr/local/eigen-3.4.0 and sudo
FindEigen3.cmake is not installed. However, using
set(Eigen3_DIR "/usr/local/eigen/share/eigen3/cmake")
seem to work. FindEigen3.cmake is in the build directory
but it is not copied to the installation directory tree.
This worked:
Changed c++11 to c++14
Changed find_package(Eigen3 QUIET) to find_package(Eigen3 CONFIG)
Another simple way is:
if the Eigen library is in /opt/eigen/3.3/Eigen
include_directories(/opt/eigen/3.3)
which is equivalent to what Jai suggested
set(EIGEN_DIR "/opt/eigen/3.3")
include_directories(${EIGEN_DIR})
You need to read official documentation:
Click here
After install Eigen from tar and compile it correctly.
CMakeLists.txt will looks like this:
find_package(Eigen3 3.3 REQUIRED NO_MODULE)
add_executable(${PROJECT_NAME} something.cpp)
target_link_libraries(${PROJECT_NAME} Eigen3::Eigen)
It will be fine work.