How to use CMake to install - cmake

I can build my projects successfully with CMake, but can I use it to install the results?
With Make I add the target install and call that from the command line. I cannot figure out if this is possible with CMake.
The final goal is to install a static library, dynamic library and corresponding header files in a platform-portable way. How I imagine it would work: On Linux, copy to /usr/include and /usr/lib. On Windows it would probably be a user-provided folder with an include and lib folder.
The install rule suggests that something like this is possible. But how do I actually use it?
Currently I do the following:
mkdir build
cd build
cmake ..
cmake --build .
Here I would expect to do something like this:
cmake --install .

You can use the command cmake --build . --target install --config Debug for installation.
CMake's build tool mode supports further arguments that are of interest in this case.
You can select the target to build by --target option, the configuration to build by --config option, and pass arguments to the underlying build tool by means of the -- option. See the documentation (Build Tool Mode) for the build-tool-mode.
In CMake 3.15 and newer, you can use the simpler cmake --install command to Install a Project:
cmake --install . --config Debug
It additionally supports --prefix, --component and --strip.

You can use the install command on your CMakeLists that will generate installation rules for your project. A basic example is shown bellow but check the cmake documentation if you need something more complex.
project (Test)
add_executable(test main.cpp)
install(TARGETS test DESTINATION bin)
Then after generate the makefiles you can ust type sudo make install and the test application will be installed on system bin folder.

Related

How to use CPack from CMake in bitbake

How is it possible to override bitbakes regular internal packaging function (do_package) and use CPack? So a normal CMake build looks like this:
cmake ../src
cmake --build ../src
cmake --build ../src --target install
So bitbake correctly handles all of this assuming I use the install command inside CMakeLists.txt and construct my recipes correctly. So building on that, I would like to use CMake's deb package generator to build my packages. Normally this would look something like this in a CMake build to generate the .deb packages after the above:
make package
or
cmake --build ../src/ --target package
I was hoping I didn't have to write a pile of custom functions.
Technically, yes. You'd have to reimplement do_package to call cmake and move the files into the right places.
Realistically, why? Packaging is mostly trivial.

Debug CMake Project Creation

I am facing a specific problem, and want advice or a way to debug it.
I am building the Allegro library from source, using: Windows 10, CMake, and Visual Studio 2015 build tools (msbuild).
Source: https://github.com/liballeg/allegro5
The problem is that when I run `cmake --build .' I am getting errors stating that the v100 toolset isn't installed, however I'm making it for Visual Studio 2015, and not 2010. If I open up the solution, or run msbuild directly, it builds perfectly fine.
Is there a way to Debug CMake that will help me see the issue?
Failing Commands:
mkdir _build
pushd _build
cmake.exe ..
cmake --build .
popd
Error:
"C:\Users\matthew\repos\allegro5_build\ALL_BUILD.vcxproj" (default
target) (1) ->
"C:\Users\matthew\repos\allegro5_build\ZERO_CHECK.vcxproj" (default
target) (2) -> (PlatformPrepareForBuild target) -> C:\Program Files
(x86)\MSBuild\Microsoft.Cpp\v4.0\V140\Microsoft.Cpp.Platform.targets(55,5):
error MSB8020: The build tools for Visual Studio 2010 (Platform
Toolset = 'v100') cannot be found. To build using the v100 build
tools, please install Visual Studio 2010 build tools. Alternatively,
you may upgrade to the current Visual Studio tools by selecting the
Project menu or right-click the solution, and then selecting "Retarget
solution". [C:\Users\matthew\repos\allegro5
_build\ZERO_CHECK.vcxproj]
Working Commands:
mkdir _build
pushd _build
cmake.exe ..
msbuild ALLEGRO.sln
popd
I've also tried forcing it to Visual Studio 2015 with commands like:
cmake.exe -G "Visual Studio 14" ..
Note: I've built my own small project with CMake and it builds correctly using CMake --build
To me it seems like something crazy with the allegro cmake build. I have searched through the source to try and find references to v100 and MSVC_2010, but found nothing of concern.
I don't want to directly use MSBuild as a work-around because I want to include allegro with ExternalProject_Add, and that fails for the same reason as building it with cmake --build.
How can I go about solving this issue?
I had a similar problem with another library (Zipper, a C++ wrapper around minizip). I was also using CMake and ExternalProject_Add in particular. Exact same error. I spent a lot of time researching the issue. I found a similar problem with another project using Gyp (have a look at the "Known issue" section). For me, the error was occurring during the install target. Changing
BUILD_COMMAND ${CMAKE_COMMAND} --build . --config Release
to
BUILD_COMMAND ${CMAKE_COMMAND} --build . --config Release --target install
INSTALL_COMMAND ""
fixed the issue. Not sure what the problem is. It seems like the default install command CMake uses in an ExternalProject picks the wrong toolset somehow...

Is there a CMake '--install' switch?

With reference to this question there is a so-called 'install' phase in CMake. I'm used to run CMake in a sequence that looks like this:
cmake ..
cmake --build . --config Debug
cmake --build . --config Release
Is there a cmake --install command line switch meant to be invoked after this?
Although I figure it is somehow related, I'm not looking for the so called install command here (I perceive this to be a function rather than a command, but this is likely a terminology issue).
No, this switch does not exist (until CMake 3.15, see my other answer).
If a project uses the install command, it generates the target install. You can call it with
cmake --build . --target install
This uses CMake's Build Tool Mode, which is an abstract interface for a couple of commands to the native build tool (e.g. make or Ninja) and can also be used to pass arbitrary arguments to the native build tool.
Beginning with version 3.15, CMake offers an install switch. From the release notes:
The "cmake(1)" command gained a new "--install" option. This may
be used after building a project to run installation without using
the generated build system or the native build tool.
Source: https://cmake.org/cmake/help/v3.15/release/3.15.html#id6
So you can use
cmake --install <dir> [--prefix <install-dir>]
The optional --prefix flag lets you override the CMAKE_INSTALL_PREFIX.

Configuring Cmake Command-Line

I'm new to using the Cmake command-line. Using the GUI I can specify a source directory and a build directory then generate. It works just fine.
When I run the command-line variant I don't get any output in the build directory.
cmake -G "Visual Studio 12 2013 Win64" --build C:\MySource\Build C:\MySource
I also get other errors because it's trying to use Win32 yet I specify Win64.
Leave out the --build option. When you do the cmake configure step (equivalent to what happens by the cmake gui), you do not use --build. After you have generated the solution and projects you may build with cmake --build . --config Debug. (You can also specify which target to build with --target MyTarget.)
cd c:\MySource\Build
cmake -G "Visual Studio 12 2013 Win64" C:\MySource
cmake --build . --config Debug
For the configure step (with the -G option), you may use a relative directory .. rather than the absolute path--either way is fine.

For CMake's “install”, what does the CONFIGURATIONS argument do?

I don't know what the CONFIGURATIONS argument of CMake's install command does. When I use CONFIGURATIONS with debug or release in installing files, no file gets installed. What happened?
Can someone explain it in more detail. It will be best if you give me some examples.
P.S. This is not the same as: For CMake's "install" command, what can the COMPONENT argument do?
From the docs:
The CONFIGURATIONS argument specifies a list of build configurations for which the install rule applies (Debug, Release, etc.).
So for example, consider the following CMakeListst.txt:
cmake_minimum_required(VERSION 2.8 FATAL_ERROR)
project(Test)
add_executable(MyTest main.cc)
install(TARGETS MyTest DESTINATION bin CONFIGURATIONS Release)
This means that
cmake --build . --target install --config Release
will place the executable MyTest (or MyTest.exe) in ${CMAKE_INSTALL_PREFIX}/bin, and
cmake --build . --target install --config Debug
won't install anything.