My question is very similar to cmake: add_custom_command / add_custom_target ignoring dependency
But the answer specified does not solve my issue, and also it is for a newer version of cmake (3.20)
I want some files (shader files) to be copied to the executable directory every time the shader source changes
So I have the following code in cmake:
add_custom_command(
OUTPUT ${CMAKE_BINARY_DIR}/Shaders.txt
COMMAND ${CMAKE_COMMAND} -E echo "Actually Copying shaders"
COMMAND ${CMAKE_COMMAND} -E copy_directory ${CMAKE_CURRENT_SOURCE_DIR}/assets/ $<TARGET_FILE_DIR:Editor>/assets
COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_BINARY_DIR}/Shaders.txt
DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/assets
)
add_custom_target(CopyShaders ALL DEPENDS ${CMAKE_BINARY_DIR}/Shaders.txt)
Now, as I understand, CopyShaders will always be built (since it is always out of date), but Shaders.txt should only be built once (after the shader source is changed), after which it is up to date
I'm trying to build the target CopyShaders using cmake --build build --target CopyShaders
If I'm using MinGW, then "Actually copying shaders" never gets printed if Shaders.txt is present, even if the assets folder containing the shaders has been modified
If I'm using MSVC, I get the following warning on the terminal:
warning MSB8064: Custom build for item "D:\Acads\Programming\opengl\SummerOfCode\build\CMakeFiles\05fb3856b7a5e1f6ce1ea66ca9091779\Shaders.txt.rule" succeeded, but specified dependency "d:\acads\programming\opengl\summerofcode\editor\assets" does not exist. This may cause incremental build to work incorrectly. [D:\Acads\Programming\opengl\SummerOfCode\build\Editor\CopyShaders.vcxproj]
Again, I do have the folder existing
I figured it out
DEPENDS should only take as input files, not folders
Replacing it with all the files inside /assets works
Related
Let's say I have a Python script which does something with just built executable. And I want CMake to rebuild that executable if the script was modified (actually it is enough to just re-run the script, but rebuild an executable is fine too).
add_executable(App src/main.cpp)
add_custom_command(
TARGET App
POST_BUILD
COMMAND "${Python3_EXECUTABLE}" ARGS "scripts/do_stuff.py" "$<TARGET_FILE:App>"
WORKING_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}"
)
How can I achieve that? add_custom_command with TARGET argument doesn't support DEPENDS argument. add_dependency(App "scripts/do_stuff.py") produces an error, because "scripts/do_stuff.py" is not a target, but just a file.
Running the script is very important for correct working of the executable so I don't want define completely separate target via add_custom_command allowing bypass script execution by building just App target.
actually it is enough to just re-run the script
So the executable does not depend on the script. So re-run the script, not the executable.
add_executable(app src/main.cpp)
add_custom_command(
OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/did_do_stuff
COMMAND "${Python3_EXECUTABLE}" "scripts/do_stuff.py" "$<TARGET_FILE:app>"
COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_CURRENT_BINARY_DIR}/did_do_stuff
DEPENDS "$<TARGET_FILE:app>"
"${CMAKE_CURRENT_LIST_DIR}/scripts/do_stuff.py"
WORKING_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}"
)
add_custom_target(do_stuff
DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/did_do_stuff
)
And build target do_stuff (or all) to run it.
I'm trying to write generic way to run executable resulted after build using CMake's way.
git clone git#github.com:gargamel/ihatesmurfs.git
cmake -E make_directory build
cmake -Sihatesmurfs -Bbuild
cmake --build build
cmake -E chdir build
Now I want to start executable but on *nix, it's like:
./output
and on Windows:
output.exe
Is there a way to escape this with any possible CMake command?
Expanding on my comment a bit, you can modify the CMakeLists.txt file of the project to include add_custom_command. If your CMake creates an executable named HateSmurfs, you can add the custom command to run the executable after compilation completes:
add_executable(HateSmurfs smurfs.cpp)
# Add this piece of code to run the executable after it is built.
add_custom_command(
TARGET HateSmurfs
POST_BUILD
COMMAND HateSmurfs
)
According to add_custom_command documentation:
COMMAND
If COMMAND specifies an executable target name (created by the add_executable() command) it will automatically be replaced by the location of the executable created at build time.
I'd like to run a command on a target after installing it. I see "cmake run script for install target?", which appears to be about running a single script after installing everything. My question is a per-target script.
What I want to do is to run patchelf on an installed binary to change the interpreter. This is much like how cmake will change the RPATH on the installed binary. Looking into how this is done, I see stuff this in cmake_install.cmake (edited for brevity):
file(INSTALL DESTINATION "/bin" TYPE EXECUTABLE FILES "program")
file(RPATH_CHANGE
FILE "$ENV{DESTDIR}/bin/program"
OLD_RPATH "build-dir"
NEW_RPATH "")
if(CMAKE_INSTALL_DO_STRIP)
execute_process(COMMAND "/usr/bin/strip" "$ENV{DESTDIR}/bin/program")
endif()
This is changing the rpath and also stripping the binary after it is installed. It seems like all I need to do is get one more execute_process put in there to run my patchelf command. Yet I can't find any way to get cmake to do that.
It appears add_custom_command(POST_BUILD ...) is very close, but I do not want to modify the binary in the build directory, only after install, like how cmake modifies the rpath.
I am having an issue with CMakes Add_External_Project functionality (more of an annoyance than anything else). Specifically, I do not understand the keys CONFIGURE_COMMAND, BUILD_COMMAND and INSTALL_COMMAND.
In the following (working) example, which downloads Google's test library, the two files at the end of the question will ensure that the third party libraries are downloaded and built (not installed).
However, when I tried to add configure and build commands as "CONFIGURE_COMMAND" and "BUILD_COMMAND" (cmake . and cmake --build) instead of having to do execute_process CMake craps out with the error message:
[ 55%] Performing configure step for 'googletest'
/bin/sh: 1: cmake .: not found
Am I trying to do something that is obviously not within the scope of the Add_External_Project functionality?
Example Files:
CMakeLists.txt
cmake_minimum_required (VERSION 3.0)
project (Test VERSION 0.1.0.0 LANGUAGES CXX)
# Download and unpack googletest at configure time
configure_file("${CMAKE_CURRENT_SOURCE_DIR}/CMakeLists.txt.in" "${CMAKE_BINARY_DIR}/googletest-download/CMakeLists.txt" #ONLY)
execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" . WORKING_DIRECTORY "${CMAKE_BINARY_DIR}/googletest-download" )
execute_process(COMMAND ${CMAKE_COMMAND} --build . WORKING_DIRECTORY "${CMAKE_BINARY_DIR}/googletest-download")
add_subdirectory("${CMAKE_BINARY_DIR}/googletest-src" "${CMAKE_BINARY_DIR}/googletest-build")
CMakeLists.txt.in
cmake_minimum_required(VERSION 3.0)
project(third-party NONE)
include(ExternalProject)
ExternalProject_Add(googletest
GIT_REPOSITORY https://github.com/google/googletest.git
GIT_TAG master
SOURCE_DIR "#CMAKE_BINARY_DIR#/googletest-src"
BINARY_DIR "#CMAKE_BINARY_DIR#/googletest-build"
CONFIGURE_COMMAND ""
BUILD_COMMAND ""
INSTALL_COMMAND ""
TEST_COMMAND ""
)
If you don't specify CONFIGURE_COMMAND at all, it will assume a CMake project and run the appropriate cmake command for you (by appropriate, I mean it will use the same CMake generator as your main build, etc.). Similarly, if you leave out BUILD_COMMAND, it will also assume a CMake project and do cmake --build for you. So in your case, just leave out those two lines and ExternalProject_Add() should do exactly what you want.
The main reason you might specify these two options as empty strings is to prevent those steps from doing anything at all. This can be useful, for example, to use ExternalProject_Add() simply for its download and unpacking functionality. This exact situation is used in a technique described here for downloading the source of GoogleTest so it can be added to your project via add_subdirectory(), making it part of your build (see also this answer and other answers to that question for some related material). I suspect this might be where your code is derived from, as the structure looks similar.
For completeness, if you find yourself in a situation where you do need to specify a CMake command, don't use a bare cmake to refer to the command to run. Instead, always use ${CMAKE_COMMAND}, which is provided by CMake as the location of the CMake executable currently being used to process the file. Using this variable means cmake doesn't have to be on the user's PATH and also ensures that if the developer chooses to run a different version of CMake other than the one on the PATH, that same cmake will still be used for the command you are adding.
You can use PATCH_COMMAND like this:
option(WITH_MBEDTLS "Build with mbedtls" OFF)
if(WITH_MBEDTLS)
ExternalProject_Add(external-mbedtls
URL https://github.com/ARMmbed/mbedtls/archive/mbedtls-2.16.1.tar.gz
UPDATE_COMMAND ""
PATCH_COMMAND ./scripts/config.pl set MBEDTLS_THREADING_C &&
./scripts/config.pl set MBEDTLS_THREADING_PTHREAD
CMAKE_ARGS
-DCMAKE_INSTALL_PREFIX:PATH=${PROJECT_BINARY_DIR}/third_party/mbedtls
-DCMAKE_TOOLCHAIN_FILE:PATH=${TOOLCHAIN_FILE}
-DCMAKE_BUILD_TYPE:STRING=Debug
-DENABLE_TESTING:BOOL=OFF
-DENABLE_PROGRAMS:BOOL=ON
TEST_COMMAND ""
)
set(MBEDTLS_PREFIX ${PROJECT_BINARY_DIR}/third_party/mbedtls PARENT_SCOPE)
endif(WITH_MBEDTLS)
In order to ensure that my Linux builds are identical regardless of the distribution the build host uses, I have packaged up my compiler and the sysroot files into a relocatable tar file and checked that into source control.
So the first step in any build (or at least, a step that must be invoked before any compile step) must be to extract this tar file.
If I was using a makefile, this would be simple to do. However, the project is using cmake and I can't figure out any way to do it with cmake. It might even be that I need this extract step invoked before cmake starts to detect the compiler: I can hard-code the compiler name but if cmake fails if it can't find the compiler then I need the unpack to happen before that test.
Is this possible with cmake?
You can use execute_process to invoke cmake's cross-platform command mode (cmake -E tar). The command would be something like:
execute_process(COMMAND ${CMAKE_COMMAND} -E tar xvf MyCompiler.bz2)
The command which causes CMake to check for a valid compiler is project, so as long as you have your execute_process call before the project call, the unpacking will be done before the compiler check.