How does PROTOBUF_GENERATE_CPP know where to pick up the protoc binary from?
I have compiled protobuf locally and would like to point my CMakeLists.txt to the installed binary ( myfolder/protobuf-install/bin/protoc ) and not the system binary ( /usr/bin/protoc )
Normally for Boost, I would just set the BOOST_ROOT to my installed folder and it will find all the include_directories, libraries, etc.
How should it be done for Protobuf. I dont see any prefix option in the FindProtobuf.cmake.
set( Protobuf_SRC_ROOT_FOLDER "${CMAKE_SOURCE_DIR}/myfolder/")
find_package(Protobuf MODULE REQUIRED)
The error is
file STRINGS file "/usr/include/google/protobuf/stubs/common.h" cannot be read.
Call Stack (most recent call first):
CMakeLists.txt:17 (find_package)
Ofcourse, the above path is in myfolder/ and not in the system folder. But why is protobuf looking for includes in the system path, when I have explicitly declared the root path as myfolder/
Module FindProtobuf.cmake has a nice description of how to hint it with various things. E.g., hinting with executable could be performed with setting Protobuf_PROTOC_EXECUTABLE variable:
The following cache variables are also available to set or use:
...
Protobuf_PROTOC_EXECUTABLE
The protoc compiler
cmake -DProtobuf_PROTOC_EXECUTABLE=myfolder/protobuf-install/bin/protoc
Also, common CMAKE_PREFIX_PATH variable works well, see that question: Hinting Find<name>.cmake Files with a custom directory.
Related
I am trying to create a simple project using SDL2 and SDL2_image extension. As SDL2_image doesn't provide official support for Find*.cmake modules, my alternative was to use pkg-config to find those libraries.
However, I built SDL2 and SDL2_image myself and installed them in a custom path (~/Library/SDL2 and ~/Library/SDL2_image).
CMake seems to be able to find SDL2 properly, but it can't find SDL2_image, even if I put the .PC file in the system default path (/usr/share/pkgconfig).
How do I tell CMake to look for a .PC file in a non-default (system) path? I need that to build a simple project using SDL2 and SDL2_image.
I've tried to put the SDL2_image.pc file in the default system path for .PC files (/usr/share/pkgconfig), but it seems not to be changing anything.
find_package(PkgConfig)
# SDL2 can be found and included
pkg_search_module(SDL2 REQUIRED sdl2)
# SDL2_image cannot be found and thus the project doesn't configure/generate.
pkg_search_module(SDL2IMAGE REQUIRED SDL2_image>=2.0.0)
Error message when running "cmake":
-- Checking for one of the modules 'SDL2_image>=2.0.0'
CMake Error at /usr/share/cmake-3.7/Modules/FindPkgConfig.cmake:637 (message):
None of the required 'SDL2_image>=2.0.0' found
Call Stack (most recent call first):
CMakeLists.txt:12 (pkg_search_module)
Find pkg-config *.pc file, and export the path:
export PKG_CONFIG_PATH="/path/lib/pkgconfig"
I have VTK6 installed on my Debian machine and it places all its CMake files under
$ ls /usr/lib/cmake/vtk-6.3/
[...]
VTKConfig.cmake
vtkModuleAPI.cmake
[...]
When I do
find_package(VTK)
in another project, it all works out fine. However,
include(vtkModuleAPI)
yields the error
include could not find load file:
vtkModuleAPI
I had always been under the impression that find_package() and include share the same search paths, specifically CMAKE_MODULE_PATH. Apparently that's not correct.
Note that
SET(CMAKE_MODULE_PATH "/usr/lib/cmake/vtk-6.3")
include(vtkModuleAPI)
does work.
Also note that I'm using CMake 3.5, so there no longer is a FindVTK.cmake as it used to be.
What are the default search paths for find_package() and include()? Why is vtkModuleAPI.cmake not found?
There are two modes of find_package, which have many differences:
Module mode tries to locate FindXXX.cmake file. The file is searched under directories listed in CMAKE_MODULE_PATH plus under directory where CMake is installed.
Config mode tries to locate XXXConfig.cmake file. The file is searched under directories listed in CMAKE_PREFIX_PATH and some other, system-specific variables. (Full algorithm see in the documentation, linked at the beginning of the post).
Command include searches modules only under directories in CMAKE_MODULE_PATH and special CMake module directory.
As you can see, command include and command find_package in module mode uses similar search paths. But in your case, VTKConfig.cmake can be searched only in config mode of find_package, which uses completely different search algorithm.
In case of VTK, CMake has shipped FindVTK.cmake file, which is used when you call find_package(VTK). But inside, this script uses find_package(VTK QUIET NO_MODULE).
If this call locates file /usr/lib/cmake/vtk-6.3/VTKConfig.cmake, it executes this script, and the script includes vtkModuleAPI.cmake one.
If your VTKConfig.cmake is not located by CMake, you may help it by setting VTK_DIR variable to /usr/lib/cmake/vtk-6.3/.
[Starting with CMake-3.1, FindVTK.cmake is no longer shipped with CMake, so find_package(VTK) immediately tries to locate VTKConfig.cmake].
In any case, modules in directory /usr/lib/cmake/vtk-6.3/ shouldn't be included directly: this directory is private for VTK.
find_package(VTK) uses FindVTK.cmake (in it's module mode, c.f. docu on find_package()), which is shipped by CMake and (in your case) should be located in /usr/share/cmake/Modules.
After adding /usr/lib/cmake/vtk-6.3 to CMAKE_MODULE_PATH, find_package(VTK) will still use the same FindVTK.cmake module.
In case you want to use another FindVTK.cmake module, prepend the path to that FindVTK.cmake module to CMAKE_MODULE_PATH.
include() will not use a find module and only sees files located in the CMAKE_MODULE_PATH.
I am trying to compile openimageio(oiio) on Linux but it's a mess since I know almost nothing about cmake. I don't want and I can't install them on my computer directly in the /usr/local/ directory and that's the problem. I successfully compiled dependencies by executing these bash commands in each library directory :
export workingdir=<path_to_my_project>
./configure --prefix=$workingdir/sdks/deploy
make install
And this works fine, my headers are in a include directory and my libraries are in a lib directory.
Here is the structure of my project :
../<path_to_my_project>
/sdks
/build
/oiio
/png # Successfully compiled
/jpeg # Successfully compiled
/zlib # Successfully compiled
/boost # Successfully compiled
/ilmbase # Successfully compiled
/openexr # Successfully compiled
/deploy
/lib # all .a, .la and .so of successfully compiled libraries
/include # all headers of successfully compiled libraries
The problem is that there is no ./configure available in the oiio library directory so I don't know how to set the prefix path, when I execute the make command, I have errors like this :
CMake Error at /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:108 (message):
Could NOT find PNG (missing: PNG_LIBRARY) (found version "1.6.21")
Call Stack (most recent call first):
/usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:315 (_FPHSA_FAILURE_MESSAGE)
/usr/share/cmake/Modules/FindPNG.cmake:105 (find_package_handle_standard_args)
src/libOpenImageIO/CMakeLists.txt:120 (find_package)
So I set variables and it makes no errors but this is not clean and I'm not sure that my libraries are correctly referenced (If I mes up the variable content, it is still working...).
set (PNG_PNG_INCLUDE_DIR "<workingdir>/sdks/deploy/include/libpng16")
set (PNG_LIBRARY_DIR "<workingdir>/sdks/deploy/lib")
Then I tried to create my own FindXXX.cmake files but some don't have a Root variable for the library so anyway I'm not sure if it correctly found the needed files, moreover, it makes errors :
CMake Error at src/cmake/modules/FindPNG.cmake:104 (include):
include could not find load file:
<workingdir>/sdks/build/oiio/src/cmake/modules/FindPackageHandleStandardArgs.cmake
Call Stack (most recent call first):
src/libOpenImageIO/CMakeLists.txt:120 (find_package)
But it finds the cmake file it anyway since other errors are correctly referenced to my file and if I print something in the cmake file it shows up when I run the make command.
Up to know, the command I am running in the oiio directory is make but I would like something that tells to the find_library function to looks other where. I could recall the function with other parameters but I can't use my own FindXXX.cmake files.
In the oiio repository, in the INSTALL file, paragraph line 43, it says to set environment variable for custom libraries, like PNGDIR, but should it point to the deploys directory or the build directory ? And they say to see CMake configuration output, maybe to know what environment variables to set, but I don't know what file they are talking.
I tried so set PNGDIR but it doesn't work, how to know if the variable name should be PNGDIR ? It can also be PNGROOT ?
export PNGDIR=<workingdir>/sdks/deploy # doesn't work
export PNGDIR=<workingdir>/sdks/build/png # doesn't work
It would be nice if someone could help me, I need this library to be compiled to use it, hope someone understood me.
Use CMAKE_PREFIX_PATH to indicate paths where find_library, find_path et al. should have a look (documentation)
Stuff like PNGDIR should no longer be used and is considered legacy that is kept for backwards compatibility. Patches for FindXXX provided by CMake to add XXX_DIR or XXX_ROOT are rejected by the CMake developers.
How do I build a VS2015 x64 project using glew 1.13.0 and CMake 3.4.0?
I prepared a minimal demo that can be found here: https://bitbucket.org/Vertexwahn/cmakedemos/src/2fbbc02b2c0567319d7be070b34391b1ef35048d/GlewDemo/?at=default
CMakeLists.txt:
cmake_minimum_required ( VERSION 2.8)
project ( GlewDemo )
find_package(GLEW REQUIRED)
set ( SRCS main.cpp )
add_executable(GlewDemo ${SRCS})
target_link_libraries(GlewDemo glew32s)
I downloaded the prebuilt binaries from here: http://sourceforge.net/projects/glew/files/glew/1.13.0/glew-1.13.0-win32.zip/download
And set the path of GLEW_INCLUDE_DIR to the corresponding directory ("C:\Users\no68koc\Downloads\glew-1.13.0\include")
But CMake gives me some errors:
CMake Error at C:/Program Files (x86)/CMake/share/cmake-3.4/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
Could NOT find GLEW (missing: GLEW_LIBRARY)
Call Stack (most recent call first):
C:/Program Files (x86)/CMake/share/cmake-3.4/Modules/FindPackageHandleStandardArgs.cmake:388 (_FPHSA_FAILURE_MESSAGE)
C:/Program Files (x86)/CMake/share/cmake-3.4/Modules/FindGLEW.cmake:44 (find_package_handle_standard_args)
CMakeLists.txt:4 (find_package)
Configuring incomplete, errors occurred!
See also "C:/build/vs2015/GlewDemo/CMakeFiles/CMakeOutput.log".
How does it work properly?
Error message
Could NOT find GLEW (missing: GLEW_LIBRARY)
is a standard message generated by FindXXX.cmake script (called via find_package(XXX)), that it is failed to set(deduce) some CMake variables, so whole package is assumed to be not found.
Most of FindXXX.cmake scripts descibes(in the comment), which variables are set by the script for user.
But only several of them describes, how user can help script in case when the script failed to find needed package at all, or if user wants script to find specific package installation instead of default one.
There is no universal approach in helping to the FindXXX.cmake script, in most cases one should analize code of the script for know variables, which can help.
In the given case (with GLEW package) analizing CMake-provided FindGLEW.cmake script reveals, that both find_path() call (which set GLEW_INCLUDE_DIR variable) and find_library() call (which set GLEW_LIBRARY variable) use no hints (HINT or PATH options) for search. But there are standard hints, which are used by both of this commands. One of these hints is ${CMAKE_PREFIX_PATH}/include directory for find_path and similar directory for find_library.
So you can use
list(APPEND CMAKE_PREFIX_PATH "C:\Users\no68koc\Downloads\glew-1.13.0")
for hint to find_library() and find_path() to search under this directory too.
Alternatively, you may set CMAKE_PREFIX_PATH variable in CMake cache either in GUI (e.g. inside Visual Studio) or via command line:
cmake -DCMAKE_PREFIX_PATH:PATH=C:\Users\no68koc\Downloads\glew-1.13.0
(Note, that using list(APPEND ...) instead of set(...) within CMakeLists.txt does not override variable in case it is set in cache too).
You may use another, 3d-party FindGLEW.cmake script
You can download it into your project (e.g., to cmake/FindGLEW.cmake) and issue
set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake)
for tell find_package() to use this script instead of default one.
Given script uses
${GLEW_LOCATION}
directory (and its subdirectories) as hint for searching in find_path() and find_library() (under PATH command's option). So you can set GLEW_LOCATION variable to installation directory:
set(GLEW_LOCATION "C:\Users\no68koc\Downloads\glew-1.13.0")
for make things work. Alternatively(and preferrably), this variable can be set in cache.
Also, given FindGLEW.cmake script uses
$ENV{GLEW_LOCATION}
directory as hint. This means that setting GLEW_LOCATION environment variable will also helps.
CMake cannot locate your GLEW. Thus you have to hint CMake.
Either include GLEW to some place, where CMake looks for components. Installing GLEW comes to mind.
Or you define the variables manually. You already did that for GLEW_INCLUDE_DIR. You have to define GLEW_LIBRARY, too.
It must be the path to the library named glew32, glew, or glew32s. With Unices it should be lib*.so maybe with some additional version numbers. With Windows it should be *.dll or *.lib.
CMake cannot find my Eigen3 package. I set an environment variable called
EIGEN3_INCLUDE_DIR
pointing to the path where FindEigen3.cmake is.
Then in the CMakelists.txt I wrote:
find_package( Eigen3 REQUIRED )
include_directories( EIGEN3_INCLUDE_DIR )
I get next message of error:
CMake Error at C:/Program Files (x86)/CMake 2.8/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:91 (MESSAGE):
Could NOT find Eigen3 (missing: EIGEN3_INCLUDE_DIR EIGEN3_VERSION_OK)
(Required is at least version "2.91.0")
Call Stack (most recent call first):
C:/Program Files (x86)/CMake 2.8/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:252 (_FPHSA_FAILURE_MESSAGE)
C:/Program Files (x86)/CMake 2.8/share/cmake-2.8/Modules/FindEigen3.cmake:76 (find_package_handle_standard_args)
test/test_quaternion/CMakeLists.txt:25 (find_package)
Any idea on what I am missing or doing wrong?
Since Eigen3 is completely header only, all you ever need is the path to the include directory. And this one, you are already defining manually anyway. So there is no real need for a FindEigen3.cmake or FIND_PACKAGE call.
Simply use
INCLUDE_DIRECTORIES ( "$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.