How to enable pkg-config support in eigen3 on Windows? - cmake

I am compiling a 3rd party library which uses the following commands to find Eigen3:
find_package( PkgConfig )
pkg_check_modules( EIGEN3 REQUIRED eigen3 )
include_directories(${EIGEN3_INCLUDE_DIRS})
The find_package( PkgConfig ) command runs correctly because I specified the PKG_CONFIG_EXECUTABLE variable. But pkg_check_modules( EIGEN3 REQUIRED eigen3 ) returns an error:
-- Checking for module 'eigen3'
-- No package 'eigen3' found
The Eigen3's official webpage says "It is not necessary to use CMake or install anything." It took me quite a while to realize this statement is wrong. So I ran the following to compile and install Eigen3 (version 3.3.5):
cmake -DCMAKE_CONFIGURATION_TYPES=Release -DCMAKE_INSTALL_PREFIX=E:\3rd-parties\eigen-3.3.5\install_ -G"Visual Studio 14 2015 Win64" ..
The compilation and installation process were both successful because I didn't see any failure in VS2015. But, when I go back to the build folder of the 3rd party library and run cmake again, I got exactly the same error. Eigen3 official website only provides an instruction using find_package, but not pkg-config.exe, so I next searched Google and find this thread. The answer says we need to "enable pkg-config support in the eigen3 cmake". I don't know how to enable it. Is there any specific CMake variable for this purpose? Since it is a new problem, and Eigen's main page says "To get help, stackoverflow is your best resource." so I come here for help. My question is: how to enable pkg-config support in eigen3? Or to put it another way: how to pass the pkg_check_modules( EIGEN3 REQUIRED eigen3 ) cmake command? Thanks a lot.
PS: I am working on Windows 10.

According to the Eigen3 sources, an option EIGEN_BUILD_PKGCONFIG is responsible on pkg-config support.
On Windows the whole option is disabled, but you may try to set it:
cmake -DEIGEN_BUILD_PKGCONFIG=ON <... other arguments>
When use pkg-config for find Eigen3 in CMake script, make sure that installation directory of Eigen3 is listed in CMAKE_PREFIX_PATH variable. (If CMake version used by a project is less than 3.1, then you need to additionally set PKG_CONFIG_USE_CMAKE_PREFIX_PATH to ON for tell pkgconfig module to use variable CMAKE_PREFIX_PATH. See more in the documentation for pkgconfig module.)

Related

CMake can't find non-default Eigen installation

I'm on Lubuntu 20.04. I have libeigen3-devinstalled with apt, which is version 3.3.7. However, for a project, I need 3.4.0.
I downloaded Eigen in a separate folder under $HOME/Libs/eigen-3.4.0, and I'm trying to get CMake to find it. I am using:
find_package(Eigen3 3.4.0 REQUIRED)
include_directories(SYSTEM ${EIGEN3_INCLUDE_DIR})
However, CMake seems to be only able to find the systemwide install, and constantly complains that it cannot fulfill the version requirement. I have tried all combinations I could of both CMAKE_PREFIX_PATH and Eigen3_DIR to no avail.
How exactly should I call CMake to make it see the folder in my home?

Cmake errors when using LLVM 5.0.0 from brew

I'm trying to use the stock LLVM 5.0.0 provided by Homebrew (MacOS High Sierra 10.13.3). LLVM is installed on my machine under /usr/local/Cellar/llvm/5.0.0/
Now, in my project, I have the following lines in CMakeLists.txt:
# Find the LLVM library
find_package( LLVM 5.0.0 REQUIRED )
include_directories( "${LLVM_INCLUDE_DIRS}" )
link_directories(${LLVM_LIBRARY_DIRS})
message(STATUS "LLVM include dirs: ${LLVM_INCLUDE_DIRS}")
If I run CMake without any parameters, I get:
CMake Error at CMakeLists.txt:74 (find_package):
By not providing "FindLLVM.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "LLVM", but
CMake did not find one.
Could not find a package configuration file provided by "LLVM" (requested
version 5.0.0) with any of the following names:
LLVMConfig.cmake
llvm-config.cmake
Add the installation prefix of "LLVM" to CMAKE_PREFIX_PATH or set
"LLVM_DIR" to a directory containing one of the above files. If "LLVM"
provides a separate development package or SDK, be sure it has been
installed.
It tells me that it couldn't find LLVM. So, I pass the path to the LLVM_DIR, like this:
cmake .. -DLLVM_DIR=/usr/local/Cellar/llvm/5.0.0/share/cmake/modules/
I would expect everything to work. Instead I get the following error:
CMake Error at CMakeLists.txt:74 (find_package):
Could not find a configuration file for package "LLVM" that is compatible
with requested version "5.0.0".
The following configuration files were considered but not accepted:
/usr/local/Cellar/llvm/5.0.0/share/cmake/modules/llvm-config.cmake,
version: unknown
For some reason the version is not present anywhere in the share/cmake/modules directory.
How can I fix this, without changing the brew-installed LLVM?
Found the answer. I was passing a wrong path to LLVM_DIR.
I just have to use another directory (buried in lib, not in share):
cmake .. -DLLVM_DIR=/usr/local/Cellar/llvm/5.0.0/lib/cmake/llvm/
Not sure why brew decided to install 2 versions of CMake helpers for LLVM, one in share and one in lib.

Why can't cmake find a package installed using Mac ports?

I installed cxWidgets as follows:
sudo install wxWidgets-3.0
In the cmake file of a project I am trying to build, find_package is called:
find_package(wxWidgets REQUIRED)
However, cmake complains that it can't find the package:
CMake Error at /opt/local/share/cmake-3.4/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
Could NOT find wxWidgets (missing: wxWidgets_LIBRARIES
wxWidgets_INCLUDE_DIRS)
My question is, given that cxWidgets is installed (I have confirmed by running port installed), why can't cmake find it?
The problem is that MacPorts has to support multiple versions of wxWidgets and I have no good idea how to automatically let CMake find the requested version.
You have two options.
The first one is to run sudo port select wxWidgets wxWidgets-3.0. Then CMake should automatically find wxWidgets 3.0.
The second option is to add an additional argument to cmake that depends on the software you are trying to compile.
Usually one of these flags should work:
-DwxWidgets_CONFIG_EXECUTABLE=/opt/local/Library/Frameworks/wxWidgets.framework/Versions/wxWidgets/3.0/bin/wx-config
-DwxWidgets_wxrc_EXECUTABLE=/opt/local/Library/Frameworks/wxWidgets.framework/Versions/wxWidgets/3.0/bin/wxrc

Linking GLEW with CMake

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)

Error with Ogre and CMake

I installed Ogre3D 1.8.1 (the source package) on Ubuntu 12.04 and everything went fine (I managed to run some samples on the Ogre interface). However, I hit a problem while I was compiling an external project (that one) that needed the OpenCV, ArUco and Ogre librarys. When I run the CMake of the project, I receive the following:
CMake Error at CMakeLists.txt:46 (find_package):
By not providing "FindOGRE.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "OGRE", but
CMake did not find one.
Could not find a package configuration file provided by "OGRE" with any of
the following names:
OGREConfig.cmake
ogre-config.cmake
Add the installation prefix of "OGRE" to CMAKE_PREFIX_PATH or set
"OGRE_DIR" to a directory containing one of the above files. If "OGRE"
provides a separate development package or SDK, be sure it has been
installed.
-- Configuring incomplete, errors occurred!
I know where the FindOGRE.cmake is, it's in the /usr/local/lib/OGRE/cmake, but I don't know how to say to CMake to look for that folder and fix this problem.
You just need to use the -D command line option along with the CMAKE_MODULE_PATH variable:
cmake . -DCMAKE_MODULE_PATH=/usr/local/lib/OGRE/cmake
Just for the record, an alternative solution would be to add the module path directly in the CMakeLists.txt. For example (tested on Debian 9):
set(CMAKE_MODULE_PATH "/usr/share/OGRE/cmake/modules/;${CMAKE_MODULE_PATH}")
Just make sure to add the line before find_package is called.
For me, it only works to set the following in CMakeLists.txt before find_package:
set(OGRE_DIR /usr/share/OGRE/build/sdk/CMake)
Note that the CMake directory is the one containing OGREConfig.cmake. For some reason, my CMake ignores CMAKE_MODULE_PATH.
Maybe, of some help for someone
For me, this solution work on manjaro:
set(CMAKE_MODULE_PATH "/usr/lib/OGRE/cmake;${CMAKE_MODULE_PATH}")
find_package(OGRE QUIET)
if (OGRE_FOUND)
include_directories( ${ogre_INCLUDE_DIR})
link_directories(${OGRE_LIBRARIES})
message(STATUS "OGRE: FOUND")
else()
message(STATUS "OGRE: NOT FOUND")
endif()