I wrote a very simple HelloWorld.c program and ran Cmake. It created a cmake_install.cmake file in my build directory. Can somebody explain to me why CMake generated the file cmake_install.cmake? What is it's purpose and how can I use it?
CMakelists.txt :
cmake_minimum_required(VERSION 3.0)
PROJECT(FirstExample)
add_executable(prog first.c)
Thanks!
You generally don't use cmake_install.cmake directly. From the v3.12 page it states:
The install() command generates a file, cmake_install.cmake, inside
the build directory, which is used internally by the generated install
target and by CPack.
With your current CMakeLists.txt, the generated file doesn't do much. To create a useful install you would need to add more INSTALL commands to your CMakeLists.txt using the syntax below.
INSTALL(TARGETS targets... [EXPORT <export-name>]
[[ARCHIVE|LIBRARY|RUNTIME|FRAMEWORK|BUNDLE|
PRIVATE_HEADER|PUBLIC_HEADER|RESOURCE]
[DESTINATION <dir>]
[INCLUDES DESTINATION [<dir> ...]]
[PERMISSIONS permissions...]
[CONFIGURATIONS [Debug|Release|...]]
[COMPONENT <component>]
[OPTIONAL] [NAMELINK_ONLY|NAMELINK_SKIP]
] [...])
For further reading on this command, check out the documentation site and wiki.
If it's desired to manually execute the script as stated by Nic30g the 3.12 page states that cmake -P accepts the following variables:
COMPONENT
Set this variable to install only a single CPack component as opposed to all of them. For example, if you only want to install the Development component, run
cmake -DCOMPONENT=Development -P cmake_install.cmake
BUILD_TYPE
Set this variable to change the build type if you are using a multi-config generator. For example, to install with the Debug configuration, run
cmake -DBUILD_TYPE=Debug -P cmake_install.cmake.
DESTDIR
This is an environment variable rather than a CMake variable. It allows you to change the installation prefix on UNIX systems. See DESTDIR for details.
As previous answer tells, the cmake_install.cmake contains the commands generated by install command from your CMakeLists.txt.
You can execute it by cmake -P cmake_install.cmake and it performs the installation of your project even on windows.
https://cmake.org/pipermail/cmake/2007-April/013657.html
Related
I'm using CMake v3.21.0 to invoke Qt's windeployqt during the install stage by the means of the install(CODE) command as follows:
install(
CODE "
execute_process(
COMMAND \"${CMAKE_COMMAND}\" -E
env PATH=\"${windeployqt_ROOT_DIR}\"
\"${windeployqt_EXECUTABLE}\"
# TODO(2021-08-25 by wolters): This is a different path when CPack is`
# used. How to check for this case and obtain the correct output path?
--dir \"${CMAKE_INSTALL_PREFIX}/${args_INSTALL_SUFFIX}\"
--no-quick-import
--no-system-d3d-compiler
--no-virtualkeyboard
--no-compiler-runtime
--no-webkit2
--no-angle
--no-opengl-sw
--verbose 0
\"\$<TARGET_FILE:${args_TARGET}>\"
)
"
COMPONENT runtime
)
This works fine if installing the project:
cmake --build . --config RelWithDebInfo --target install
But when creating a CPack package the files created by windeployqt are not part of the package (ZIP in this case):
cpack -G ZIP -C RelWithDebInfo -D CPACK_COMPONENTS_ALL="runtime"
I know that the issue is the usage of ${CMAKE_INSTALL_PREFIX} in the CODE.
For the install target this is correct.
For the package target this is not correct. Instead the build directory for the current CPack generator should be used, e.g. ${CMAKE_CURRENT_BINARY_DIR}/_CPack_Packages/win64/ZIP/${CPACK_PACKAGE_FILE_NAME}.
My questions are:
Is there a way to differentiate between install and package target in the CODE section? (pseudo-code: if(CMAKE_IS_PACKAGING))
If there is a way: Is it possible to obtain or dynamically build the directory path to the actual CPack temporary "install" directory?
If both problems can be solved the files generated by windeployqt should be part of the packages generated by CPack.
The variable CMAKE_INSTALL_PREFIX should not be expanded in the CMakeLists.txt, as you are doing. Its actual value at invocation time is available inside the install(CODE) fragments.
Consider the following snippet:
cmake_minimum_required(VERSION 3.21)
project(test NONE)
install(CODE [[message(STATUS "HERE: ${CMAKE_INSTALL_PREFIX}")]])
Note that [[ ... ]] escapes variable expansions (you could also use backslashes). Now if you configure this project with -DCMAKE_INSTALL_PREFIX=/tmp/install, you'll see the message print as you expect.
$ cmake -S . -B build -DCMAKE_INSTALL_PREFIX=/tmp/install
-- Configuring done
-- Generating done
-- Build files have been written to: /home/alex/test/build
$ cmake --build build/ --target install
[0/1] Install the project...
-- Install configuration: ""
-- HERE: /tmp/install
If you now run the install script again without reconfiguring or rebuilding, it will still work:
$ cmake --install build/ --prefix /tmp/other-prefix
-- Install configuration: ""
-- HERE: /tmp/other-prefix
This is how CPack runs your install rules. It does not use the configuration-time value of CMAKE_INSTALL_PREFIX. It expects your project to be relocatable (i.e. bug-free).
I have a list of various files that I want to install, by executing a resulting INSTALL project. This works, but sometimes files are no longer available, when the install operation is executed. Environment is a build server, where files get moved around -> this causes the build to be faulty.
An easy way to fix this behaviour is in the OPTIONAL parameter of the install command. So my question is: Is there a way to output warnings at runtime, if the install command failed?
Here is my code, to recreate the issue. In the src directory there are files "1.txt" and "2.txt". I build the cmakelists.txt and then delete "2.txt". After that, I execute the INSTALL solution I got.
cmake_minimum_required(VERSION 3.0)
project(documentation)
set(SOURCEDOCUMENTATION "D:/projects/side_master/src/documentation/src")
set(TARGETDOCUMENTATION "D:/projects/side_master/src/documentation/tgt")
file (GLOB files_to_install "${SOURCEDOCUMENTATION}/*")
foreach(file_to_install ${files_to_install})
install(FILES ${file_to_install} DESTINATION ${TARGETDOCUMENTATION} OPTIONAL)
endforeach()
The error (without the OPTIONAL parameter):
-- Install configuration: "Debug"
-- Installing: D:/projects/side_master/src/documentation/tgt/1.txt
CMake Error at cmake_install.cmake:56 (file):
file INSTALL cannot find
"D:/projects/side_master/src/documentation/src/2.txt".
What I want to get is a generated message, like this:
File "D:/projects/side_master/src/documentation/src/2.txt" not found.
You could make use of the install(SCRIPT ...) or install(CODE ...) signatures of the CMake install command, to run custom installation steps specific to your use case. The custom steps here would check for the existence of the files (using CMake's EXISTS logic) to be installed, and print a warning message if the file does not exist. The custom installation command could look something like this:
install(CODE "
if(NOT EXISTS ${file_to_install})
message(WARNING \"File ${file_to_install} not found during installation.\")
endif()
")
I'd like to run a command on a target after installing it. I see "cmake run script for install target?", which appears to be about running a single script after installing everything. My question is a per-target script.
What I want to do is to run patchelf on an installed binary to change the interpreter. This is much like how cmake will change the RPATH on the installed binary. Looking into how this is done, I see stuff this in cmake_install.cmake (edited for brevity):
file(INSTALL DESTINATION "/bin" TYPE EXECUTABLE FILES "program")
file(RPATH_CHANGE
FILE "$ENV{DESTDIR}/bin/program"
OLD_RPATH "build-dir"
NEW_RPATH "")
if(CMAKE_INSTALL_DO_STRIP)
execute_process(COMMAND "/usr/bin/strip" "$ENV{DESTDIR}/bin/program")
endif()
This is changing the rpath and also stripping the binary after it is installed. It seems like all I need to do is get one more execute_process put in there to run my patchelf command. Yet I can't find any way to get cmake to do that.
It appears add_custom_command(POST_BUILD ...) is very close, but I do not want to modify the binary in the build directory, only after install, like how cmake modifies the rpath.
I've got CMake (3.02) installing to a DESTDIR when I invoke:
$ make -C build DESTDIR=$(pwd)/build/rootfs install
This results in a file layout that I'm happy with: binaries are located in the .../build/rootfs/usr/local/bin directory and the init scripts are in .../build/rootfs/etc/init.d. To accomplish that, I used a mixture of relative and absolute paths in my CMakeLists.txt file:
set(CPACK_SET_DESTDIR ON)
...
INCLUDE(CPack)
...
set(ROOTFS_BIN_DIR bin)
set(ROOTFS_ETC_INITD_DIR /etc/init.d)
...
INSTALL(TARGETS myDaemon DESTINATION ${ROOTFS_BIN_DIR})
INSTALL(PROGRAMS myDaemon.sh RENAME myDaemon DESTINATION ${ROOTFS_ETC_INITD_DIR})
With that, I think 'working', I'm trying to create a simple tarball package which will eventually become a debian package (with pre/post install/remove scripts) but when I invoke:
$ make -C build DESTDIR=$(pwd)/build/rootfs package
I'm getting errors because cpack is attempting to write my init scripts to the system's /etc/init.d directory (instead of $(pwd)/build/rootfs/etc/init.d). If I wanted that, then $sudo !! would solve the problem. The error (replaced full path with ...):
CMake Error at .../build_src/cmdServer/cmake_install.cmake:44 (file):
file INSTALL cannot copy file
".../src/cmdServer/cmdServer.sh" to
"/etc/init.d/cmdServer".
I'm not using a lot of CPACK directives: in my top level CMakeLists.txt file I have:
SET(CPACK_SET_DESTDIR ON)
SET(CPACK_GENERATOR TGZ)
INCLUDE(CPack)
How can I package my init scripts correctly?
I've been referencing:
https://cmake.org/pipermail/cmake/2008-April/020833.html
and https://cmake.org/pipermail/cmake/2006-November/011890.html
Describe difference between these two command lines:
C:\xxxxx> cmake -help
Usage
$ cmake [options] <path-to-source>
$ cmake [options] <path-to-existing-build>
Specify a source directory to (re-)generate a build system for it in the
current working directory. Specify an existing build directory to
re-generate its build system.
The last description does not give me how to use the first, or the second.
Could you explain it to me?
When you use you do an in-tree build (cmake .), there is no difference.
When you do an out-of-tree build, there is a difference.
Suppose your project lives in ~/foo and your current directory is ~/foo/build
You have to run cmake .. for the first build. But for subsequent reconfigures, you can use cmake . because there is already a build there.
This command:
cmake [options] <path>
works as follows:
if <path> is not a valid (that is, already configured) CMake build directory, it is assumed to contain a CMakeList.txt. CMake will configure the current working directory as a build directory using <path>/CMakeLists.txt for source directory.
if <path> is a valid CMake build directory, the command reconfigures that directory using the source directory assigned when you first configured that build directory
So the common usage patterns are:
initial configuration:
mkdir my-build-dir
cd my-build-dir
cmake [options] my-source-dir
subsequent (re)configurations:
cmake [options] my-build-dir # current-work-dir is not important
alternative (initial) configuration using undocumented options:
cmake -Hmy-source-dir -Bmy-build-dir [options] # cwd is not important