CMake set default resource/asset directory - c++

I'm trying to make a simple sfml/c++ application using cmake.
Suppose I need to refer to a simple foo.png somewhere in my code. I found out that I can only do so if it lies inside of the build folder. This is the folder from where I invoke the cmake .. command and where all of my cmake files (apart from CMakeLists.txt and library modules, such as FindSFML.cmake) reside.
I don't want it to look there... but in a folder that is called art, located in build's parent directory. I want to do this to keep the "build" folder not essential to the project (in the sense that anyone can build the project without relying on stuff that's inside of it).
From what I've seen - looking online, that is - everyone tends to suggest to use the file(COPY ...) command (or something similar) to copy all of the needed assets/resources inside of another folder similar to my before-mentioned build folder (I know there must be a technical term for this... build directory, perhaps?), and profit. But is this copying process really necessary? Shouldn't you be able to just specify a different directory from which to load your assets/resources?
Or maybe I've got it all wrong... cmake is just hard to understand sometimes. Thanks in advance and excuse my lack of technical knowledge.

I found a solution using symbolic links and the add_custom_command function.
Here it is (assuming the layout described above):
set (source "${CMAKE_SOURCE_DIR}/resources")
set (destination "${CMAKE_CURRENT_BINARY_DIR}/resources")
add_custom_command(
TARGET ${PROJECT_NAME} POST_BUILD
COMMAND ${CMAKE_COMMAND} -E create_symlink ${source} ${destination}
DEPENDS ${destination}
COMMENT "symbolic link resources folder from ${source} => ${destination}"
)
I actually got this from a blog... here's the link to the article for good citizenship: http://qrikko.blogspot.it/2016/05/cmake-and-how-to-copy-resources-during.html
Have a nice day.

Related

CMake not building a library when added as a subdirectory

I added the xgboost library as a git submodule of my project and I'm trying to add it to cmake as a subdirectory. Unfortunately it's not working. A simple hello world project with the following CMakeLists.txt replicates the error that I'm getting.
cmake_minimum_required(VERSION 3.2)
project(foo)
add_subdirectory(xgboost)
add_executable(${PROJECT_NAME} foo.cpp)
target_link_libraries(${PROJECT_NAME} xgboost)
After building the library there is nothing in the xgboost/lib directory so I get the following error.
clang: error: no such file or directory:
'/Users/.../myproject/xgboost/lib/libxgboost.dylib'
I think that the problem is generated in their CMakeLists file since they have two different targets. Maybe cmake is choosing the wrong target but I'm not familiar enough with cmake to figure it out. The following code is from xgboost's CMakeLists.
# Executable
add_executable(runxgboost $<TARGET_OBJECTS:objxgboost> src/cli_main.cc)
set_target_properties(runxgboost PROPERTIES
OUTPUT_NAME xgboost
)
set_output_directory(runxgboost ${PROJECT_SOURCE_DIR})
target_link_libraries(runxgboost ${LINK_LIBRARIES})
# Shared library
add_library(xgboost SHARED $<TARGET_OBJECTS:objxgboost>)
target_link_libraries(xgboost ${LINK_LIBRARIES})
set_output_directory(xgboost ${PROJECT_SOURCE_DIR}/lib)
#Ensure these two targets do not build simultaneously, as they produce outputs with conflicting names
add_dependencies(xgboost runxgboost)
My questions in order of importance are:
Is there any way to fix it without modifying xgboost's CMakeLists.txt file?
Is it reasonable to try to add xgboost to my project as a git submodule?
Is there any reason cmake is not instructing to build the library?
Note: There were several edits to this question since I tried to narrow down the problem and to provide more information.
(I would love to ask for few things beforehand in the comment section, but I have too low reputation to do so, so I will just give it a shot ;))
I have few suspects, and one of them is ${CMAKE_SOURCE_DIR} of the submodule's root CMakeLists.txt. Although the paths are set properly when you run that CMakeLists.txt alone, cmake gets confused the moment you add it as your subdirectory. Have you looked into another directories for your output binaries?
First I would suggest testing this hypothesis, and then I would suggest writing similar, but separate CMakeLists.txt file for xgboost library, and then substitute it in the project temporarily. Unfortunately the CMakeLists.txt filename is hardcoded and there is no possibility to have two files of that kind in one directory; so it seems that the answer to 1) is, that you rather have to change the file.
For the 2): as long as it does not require huge additional logic in your CMakeLists.txt, it makes sense. Other viable option is to create an install target, which you can use to install your xgboost library locally (using CMAKE_INSTALL_PREFIX(doc) variable), and then add the installation path to your CMAKE_LIBRARY_PATH(doc).

Building tensorflow serving client with cmake

I searched for the best way to do this, but I was unable to find a clear answer.
Was anyone able to build a tensorflow-serving client using cmake?
I am having difficulties with generating CPP files from proto, since they are needed for prediction service. Those proto files also include proto files from tensorflow.
so far I have come up with this:
project(serving C CXX)
find_package(Protobuf REQUIRED)
file(GLOB_RECURSE proto_files RELATIVE ${serving_SOURCE_DIR}/tensorflow/
"${serving_SOURCE_DIR}/tensorflow/*.proto")
set(PROTOBUF_GENERATE_CPP_APPEND_PATH OFF)
include_directories(${PROTOBUF_INCLUDE_DIRS})
include_directories( ${CMAKE_CURRENT_BINARY_DIR} )
PROTOBUF_GENERATE_CPP(PROTO_SRCS PROTO_HDRS ${proto_files})
add_library(tf_protos ${PROTO_SRCS} ${PROTO_HDRS})
target_link_libraries(tf_protos PUBLIC ${PROTOBUF_LIBRARIES})
Cmake builds successfully but the make command gives me an error:
No rule to make target '../tensorflow/tools/proto_text/test.proto', needed by 'tensorflow/tools/proto_text/test.pb.cc'. Stop.
To overcome the problem of .proto includes not being found I used command
set(PROTOBUF_GENERATE_CPP_APPEND_PATH OFF)
which was explained here: https://groups.google.com/forum/#!topic/protobuf/eow2fNDUHvc
My current folder structure is
serving/
CmakeLists.txt
tensorflow/
tensorflow_serving/
apis/
Folder apis contains .proto files that are needed in the client implementation and they include .proto files from the folder tensorflow.
Is this even the right way to go?
Any help/advice would be much appreciated.
I was able to get it to work in the layout you have where the CMakeLists.txt file is placed in the same level as the serving repository here. You'll need to install Tensorflow too though (using tensorflow_cc).
However, you probably don't want to muck with a fork of the official tensorflow/serving repository so I went a step further and moved the CMakeLists.txt out so you can just submodule the official repository. I made an example here
The gist is that the protobuf CMake submodule expects proto files to be laid out in the same directory from which it's called. I made some modifications to the submodules to let us call it from a level above serving and to ensure it invokes the compiler with the include paths in the right order to support the nested structure of the proto files in serving/tensorflow_serving/apis/* (and placing it accordingly in the specified build directory)
Hopefully someone else with better knowhow can make this better!
These worked for me.
https://github.com/wardsng/inception_cmake
https://github.com/FloopCZ/tensorflow_cc
You can choose a private install directory instead of the default, e.g. /usr/local/...
cmake -DCMAKE_INSTALL_PREFIX= ..

Isolating gitsubmodule projects in CMake

I'm trying to manage my C++ project dependencies using CMake and gitsubmodules. I'm following the layout described here: http://foonathan.net/blog/2016/07/07/cmake-dependency-handling.html and it's worked really well for me on smaller projects. But I've started to use it on much larger projects and I'm hitting some issue with CMake.
My current setup
All my external build dependencies are in a contrib/ subfolder inside my main project. Each is a submodule and has its own separate directory.
/contrib
- /eigen
- /curl
- /leapserial
- /zlib
- /opencv
etc.
The contrib/CMakeListst.txt simply initializes the submodule and adds the subdirectory for each external dependency
# EIGEN
execute_process(COMMAND git submodule update --recursive --init -- eigen
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
# options..
add_subdirectory(eigen EXCLUDE_FROM_ALL)
# CURL
execute_process(COMMAND git submodule update --recursive --init -- curl
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
# Initialize cache with CMake build options..
add_subdirectory(curl EXCLUDE_FROM_ALL)
# LEAP SERIAL
execute_process(COMMAND git submodule update --recursive --init -- leapserial
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
# Initialize cache with CMake build options..
add_subdirectory(leapserial EXCLUDE_FROM_ALL)
# ZLIB
execute_process(COMMAND git submodule update --recursive --init -- zlib
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
# Initialize cache with CMake build options..
add_subdirectory(zlib EXCLUDE_FROM_ALL)
# OPENCV
execute_process(COMMAND git submodule update --recursive --init -- opencv
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
# Initialize cache with CMake build options..
add_subdirectory(opencv EXCLUDE_FROM_ALL)
This setup has worked fantastically for me:
It's system/packagemanager independent. You don't need to install any libraries to get started developing
I can maintain the exact versions of my dependencies by setting the submodule to a particular commit. There are no surprises with some external library breaking your build
Adding the libraries to my build in the root CMakeListst.txt is trivial. Since I have the target available I just have something like
add_executable(someProjectImWorkingOn
${CMAKE_CURRENT_SOURCE_DIR}/src/main.cpp )
target_link_libraries(someProjectImWorkingOn
opencv_world
eigen
zlib
etc.)
when you hook up an existing library target to your own target executable/library CMake will automatically (through the target interface) add include directories to your target and add any other necessary options the library target requires for it to be used
I can pick a toolchain/compiler-option/build-type in the root CMakeLists.txt and it'll propogate to all the subprojects (I need to build for multiple systems. So this is a big big deal)
Since it's all in one "mega-project" it makes it very easy to hook up to rtags/kdevelop/clion to navigate not on your own code, but also the library code
Some issues that I can't resolved:
1
Subdirectories will define targets with the same name. In the example I gave, both Eigen OpenCV as well as another library define an 'uninstall' target
I tried to update the
add_subdirectory(blah)
to
add_subdirectory(blah EXCLUDE_FROM_ALL)
but this doesn't fix the issue for some reason
Enabling the variable ALLOW_DUPLICATE_CUSTOM_TARGETS kinda works.. but this is a hack, only work with Make files, and the libraries are essentially still "mixing" so it's still an issue
2
The second issue came up in LeapSerial but illustrates a bigger issue. The project no longer knows it's own name. LeapSerial tried to determine the version of LeapSerial, but when it asks for the project version it's getting the root project version. Ie. when cmake code in a subproject asks for "what project am I in" it's getting the root project, and not the immediate project it's in.
So again, the parent "namespace"s are leaking everywhere. This is bound to create more and more issues down the line. I need to the submodules to be self-contained
Is there are a cleaner solution?
ExternalProjectAdd might solve some of these problems, but has a lot more issues of its own. It's a real non-starter b/c it doesn't do most of what I've listed. The central issue is that it doesn't expose the sub-project's targets - and just vomits back variables that you then have to juggle
As the asker said in the comments, they resolved their issue by using the Hunter package manager. The rest of this answer is about actually answering the question as posed.
Concerning your first issue with target name clashes when using add_subdirectory-based approaches to using dependencies, a very similar (or essentially the same?) question has also since been asked here: How to avoid namespace collision when using CMake FetchContent?. When the clashes are between targets from different project dependencies, there's nothing you can do right now except politely ask the project maintainers to consider modifying their non-import/export target names to be namespaced like.
For example, for a library target, that might look like:
add_library(projectname_targetnamepart)
add_library("importexportnamespacename::targetnamepart" ALIAS projectname_targetnamepart)
set_target_properties(projectname_targetnamepart PROPERTIES EXPORT_NAME targetnamepart)
set_target_properties(projectname_targetnamepart PROPERTIES OUTPUT_NAME targetnamepart)
install(TARGETS projectname_targetnamepart EXPORT projectname_targets ...)
install(EXPORT projectname_targets NAMESPACE "importexportnamespacename::" ...)
There's a Kitware issue ticket by Craig Scott proposing a CMake feature for Project-level namespaces. Here's an excerpt:
A common problem when pulling in subprojects using add_subdirectory() is that target names must be unique, but different subprojects might try to use the same target name, which results in a name clash. This issue proposes to introduce the concept of a project namespace to address this and related name uniqueness problems (this is the primary goal of this issue).
Sometimes the upstream maintainer will just decline to support the add_subdirectory / FetchContent use-case. That's the case with OpenCV, as shown in this issue ticket (#16896). As for eigen, there's an open ticket that hasn't had any activity in a while (#1892).
Concerning your second issue, there's not enough detail in your question post to confidently troubleshoot. What is LeapSerial? Are you referring to the leapmotion/leapserial GitHub repo? What version and what commit are you referring to? At the latest commit before the time of your question post, 41515db, it's not immediately obvious what's wrong.
Variables in CMake are scoped by directory, so even if a project is added by add_subdirectory and doesn't used the <PROJECT-NAME>_VERSION variable and instead uses the more general PROJECT_VERSION variable, it should be okay. It just shouldn't attempt to use the CMAKE_PROJECT_VERSION variable to get its own version, since that one is fixed to refer to the top-level project's version.

Can I manually use CMake's cpp file dependency-scanner in my cmake code?

I am trying to add a custom target with CMake that executes one command for each given .cpp file. The command should only be re-executed when the source file itself or one of the included source files changes. AFAIK to achieve this I need a list of all the included files and add them to the DEPENDS option of the add_custom_command() calls that belong to my custom target.
So is there a built-in way to get that list of included files?
I know about the IMPLICIT_DEPENDS option of the add_custom_command() function but it only works for Makefile generators. I would like to make this work for all generators.
Thank you for your time
Edit:
As requested I will post some cmake code to show what I want to achieve.
I want to add a custom target, that runs clang-tidy on all the given .cpp files. When incrementally building the custom target the clang-tidy commands should be re-run whenever a .cpp file or one of its directly or indirectly included header files is changed. Just like re-runs of the compiler are handled.
# ----------------------------------------------------------------------------------------
# mainTargetName The name of the target that shall be analyzed
# files A list of all the main targets .cpp files
#
function( addStaticAnalysisTarget mainTargetName files )
set(targetName runStaticAnalysis_${mainTargetName})
set(command "clang-tidy-4.0 -checks=* -p ${CMAKE_BINARY_DIR}")
foreach( file ${files} )
get_filename_component( baseName ${file} NAME_WE)
set(stampFile ${CMAKE_CURRENT_BINARY_DIR}/analyze_${baseName}.stamp )
set(fullFile ${CMAKE_CURRENT_SOURCE_DIR}/${file})
set(commandWithFile "${command} ${fullFile}")
separate_arguments_for_platform( commandList ${commandWithFile})
add_custom_command(
OUTPUT ${stampFile}
DEPENDS "${fullFile}"
IMPLICIT_DEPENDS CXX "${fullFile}"
COMMAND ${commandList}
COMMAND cmake -E touch "${stampFile}" # without creating a file as a touch-stone the command will always be re-run.
WORKING_DIRECTORY ${CPPCODEBASE_ROOT_DIR}
COMMENT "${commandWithFile}"
VERBATIM
)
list(APPEND stampFiles ${stampFile})
endforeach()
set_source_files_properties(${stampFiles} PROPERTIES GENERATED TRUE) # make the stamp files known to cmake as generated files.
add_custom_target(
${targetName}
DEPENDS ${stampFiles}
)
endfunction()
The problem with that is, that it does not seem to work. When I change included files clang-tidy is not re-run for the affected files.
I used the "Unix Makefile" generator for this example so it should work at least with make. Any hints why it doesn't?
My hopes where that I could achieve the desired behavior for all generators by somehow getting the file-dependencies at cmake time and then adding them to the ''''DEPENDS'''' list. But the dependency scanning must be done each time the command is run, so it can not be done at cmake time. This means that the scanning must be implemented by cmake which it currently is not.
A guy with similar problems:
https://gitlab.kitware.com/cmake/cmake/issues/16830
Edit 2:
I think the problem that the IMPLICIT_DEPENDS option was not working was because I did not use correct filenames. I changed that in the code snipped, but I have not yet tested if it works in the project.
I think the answer to my question is ...
No, you can not use cmakes dependency scanner in the cmake code.
That makes sense, because this problem can not be solved at cmake time, because the dependencies of a .cpp file may change without cmake being re-run.
The problem must be solved within cmake itself at make time. This is done when using the IMPLICIT_DEPENDS option.
Also, I tried to solve a Problem that I did not really have, because at this point I can only run clang-tidy on linux anyways. However, clang-tidy may become available on windows as well and then I may have the problem again.
To sum the comments up:
Tambre stated that CMake is not a compiler and therefore can not do that.
I think this is wrong. According to this article, CMake can parse cpp include dependencies because make has no such dependency searcher itself. That was news to me, but I mostly live on Windows so I am not that familiar with make. It could also be possible that in the meantime make was extended to do its own dependency searching. Also this explains why the IMPLICIT_DEPENDS option is only available for make.
Florian pointed out that it is not necessary to create an own custom target for running clang-tidy. Instead, one can use the CXX_CLANG_TIDY target property to run clang-tidy for each file after compiling it. This means however, that static-analysis can not be separated from the build which could lead to inacceptable buildtimes.
There is the cmake -E cmake_depends command line, that could be used to retrieve dependencies at cmake time. But as stated above, I erroneously thought that I needed the dependencies at cmake time, while I needed them at runtime.
The IMPLICIT_DEPENDS options did not work because I had an error in my cmake code.

The right way to structure my c++ project with cmake?

I have been struggling with this for quite a while, and my adventures with cmake have only resulted in hackish solutions that I am pretty sure are not correct.
I created a library that consists of several files, as follows:
-libfolder
-codepart1folder
-CMakeLists.txt
-codepart1.cpp
-codepart1.hpp
-codepart2folder
-codepart3folder
-lib.cpp
-lib.hpp
-CMakeLists.txt
I wrote a CMakeLists file to compile the library (after some experimentation), and I can generate a lib.a file. Now I would like to include this code as a library in other projects, and access it through the interface in lib.hpp. What is the best way to do this, in terms of directory structure, and what I need to put into CMakeLists.txt in my root project?
My current attempt has been to add -libfolder as a subfolder to my current project, and add the commands:
include_directories(${PROJECT_SOURCE_DIR}/libfolder)
link_directories(${PROJECT_BINARY_DIR}/libfolder)
add_subdirectory(libfolder)
target_link_libraries(project lib)
When I run make, the library compiles fine, but when project.cpp compiles, it complains that it cannot find codepart1.hpp (which is included in lib.hpp, included from project.cpp).
I suspect that this is the wrong way about doing this, but I cannot wade through the CMake documentation and find a good tutorial on setting up projects like this. Please help, CMake gurus!
The clean way to import one CMake project into another is via the find_package command. The package declaration is done by using the export command. An advantage of using find_package is that it eliminates the need to hard-code paths to the package's files.
Regarding the missing hpp file, you didn't include codepart1folder, so it's not on the include path.
Ok, so after consulting a coworker of mine who is a CMake guru, it seems CMake does not have support for what I am trying to do, leaving one with 3 options:
Add all of the dependencies to the parent projects CMakeLists.txt - not very clean, but it will get the thing to work. You'll have to do this for every project you add the code to, and go back and fix things if your library changes.
clean up your library headers. This is done through some compiler hackery. The idea is to forward-declare every class, and use only pointers or boost::shared_ptr, and then include the dependencies only in the cpp file. That way you can build the cpp file using all the findpackage stuff, and you get the bonus of being able to use the lib by only including the header and linking to the library.
Look into build systems. Having portable code and fast code compilation with complex dependencies is not a solved problem! From my investigations it turned out to be quite complicated. I ended up adopting my coworkers build system which he created himself in cmake, using things he picked up from Google.
Looking at your post you don't seem to add 'codepart1folder' to the includes anywhere. How are you including codepart1.hpp as:
#include <codepart1.hpp>
#include "codepart1folder/codepart1.hpp"
I don't think there is a standard accepted way to structure cmake projects. I've looked at a bunch of cmake repos and they tend to have differences. Personally I do the following:
-project
CMakeLists.txt
-build
-cmake
OptionalCmakeModule.cmake
-src
-Main
Main.cpp
Main.hpp
-DataStructs
SomeTree.hpp
SomeObject.hpp
-Debug
Debug.hpp
-UI
Window.hpp
Window.cpp
Basically that dumps all the source code into 1 directory, then you perform an out of source build with: 'mkdir build && cd build && cmake .. && make' in the projects root folder.
If you have separate libs as part of your project, then you might want a separate libs directory with another subfolder for your specific lib.
I have some of my repos on: https://github.com/dcbishop/ if you want to look at the CMakeLists.txt files.
The main problems with my project structure are that I use the FILE_GLOB which is apparently the 'wrong' way to do things (if you add files after running 'cmake ..' then they won't be picked up hen you do a 'make'). I haven't figured out what the 'right' way to do it is (from what I can see it involves keeping a separate list of files) I also only use 1 CMakeLists.txt file.
Some projects also choose to separate their cpp and hpp files into separate directories. So you would have an include and src folders (at least for the hpp files that are intended to be used externally). I think that would mainly be for projects that are mainly large libraries. Would also make installing header files much easier.
You are probably missing
include_directories(${PROJECT_SOURCE_DIR}/libfolder/codepart1folder)
In such a case you might want to set( CMAKE_INCLUDE_CURRENT_DIR on) to add all folders to the include directory path variable.
Check cmake's output on the command line whether the correct include folders are set or not. Additionally you can always use message() as "print debugging" for cmake variables.
In case of include directories however you need to read the directory property to see what is actually in the include directories.
get_property(inc_dirs DIRECTORY PROPERTY INCLUDE_DIRECTORIES)
message("inc_dirs = ${inc_dirs}")
I hope this helps you figuring out what is missing.
Edit
I just saw your comment about added codepart1folder in the libfolder. It is only available in the libfolder's include_directory path and not propagated to the root folder.
Since the include codepart1.hpp is present in the lib.hpp however you need to have it also available in the project path otherwise you will get missing declaration errors when you build your project.