I want to use add_custom_command to generate a file. I know I can use add_custom_target to set the DEPENDS to invoke the command. But this will also create a target(like in visual studio, it will create a .vcxproj). I use another add_custom_command, and then set the DEPENDS but it does not work. Why? Which level dependency can invoke it?
Are there any methods to invoke the add_custom_command like make install invokes the install command .
The add_custom_command() function corresponds to Makefile's rule. It list commands which are needed to produce some file. If you wish to be able to run in from make invocation, you should wrap it into `add_custom_target(tgt DEPENDS cmd), just as you said.
So, there is no way to execute custom_command's without creating custom_target's for them.
Related
A bit of context first - I'm working on converting a CMake build system to an internal build system. For this I iterate BUILDSYSTEM_TARGETS and use get_property to get all the properties I need and everything works fine, except some files are missing from the build. After checking the CMakeLists.txt files from the original build system I realized configure_file is used in many and quite random places.
I assume CMake is storing configure_file calls internally. If this is the case, is it possible to access this?
Tsyvarev's answer of redefining configure_file works, but be aware that Craig Scott (one of the maintainers of CMake) has an article recommending against redefining CMake commands. Using the internal underscore-prefixed commands is relying on undocumented behaviour that can change in future versions. Using this trick can also result in infinite recursion.
While for your scenario it works fine, if you want to avoid using that trick, you can use the --trace* arguments to the cmake command.
--trace puts cmake in trace mode, which will print a trace of all calls made and from where.
--trace-expand is like --trace, but with variables expanded.
--trace-format=<format> lets you choose between human (a human readable format (the default value)), or json-v1, which prints JSON.
--trace-redirect=<file> puts cmake in trace mode and redirects trace output to a file instead of stderr.
So you could use the human format and grep for configure_file, or you could use the json-v1 format and write a script in a lanugage of your choice to search the JSON for calls to configure_file. You could also possibly use a comandline tool like jq to do the search.
You could redefine configure_file as a function (or macro) at the beginning of the project's CMakeLists.txt. That way allows you to run arbitrary code every time the function is invoked in the project.
Inside redefining function you could implement the logic which you need. For call original function in the redefining one, use underscore-prefixed name (_configure_file):
function(configure_file input output)
# ...
# Do something with the 'output' file. E.g. add it to the global list.
# ...
# After custom processing call original function with all parameters.
_configure_file(${input} ${output} ${ARGN})
endfunction()
I am using cmake and cpack and wix to build and deploy my project. The installer has some properties that user can enter via GUI or MSI-command-line options.
I set default property values in my CMakeLists.txt using:
set(CPACK_WIX_PROPERTY_<PROPERTY> <value>)
The problem is that if I change these values, I should rerun cmake command before cpack command.
I am looking for a way to change default value of these properties without need for rerunning cmake.
I tried adding additional wxs files using CPACK_WIX_EXTRA_SOURCES or patching generated files with additional xml files using CPACK_WIX_PATCH_FILE, but couldn't find the right code to put in wxs or xml files to accomplish my goal.
I tried The SetProperty command and found out its behavior is not easy to control, I gave up when I saw the user provided values don't replace the initial values and suggested solution at https://web.archive.org/web/20180205001358/http://windows-installer-xml-wix-toolset.687559.n2.nabble.com/Unable-to-override-SetProperty-value-with-Edit-Control-value-td7591569.html didn't work. I hope there is a simple way, but even a complex answer using SetProperty is allright.
I am looking for a way to change default value of these properties without need for rerunning cmake.
A script specified in CPACK_PROJECT_CONFIG_FILE variable is the one, which affects on CPack, but which changing doesn't require cmake to re-run. So you may place setting of CPACK_WIX_PROPERTY_<PROPERTY> here: Changing this setting would require only to re-run CPack without re-run cmake on the main project.
Also, when the script specified in CPACK_PROJECT_CONFIG_FILE variable is parsed, CPACK_GENERATOR variable contains the exact CPack generator which is currently processed. This opposites to behavior of the variable inside CMakeLists.txt, when it contains a list of generators.
The various clang-based completion tools (like youcompleteme) need to be told what compiler flags a source is to be compiled with. It would be nice if the compiler options to be used could be extracted from the project files. What would be easiest way to extract the flags (automatically, not manually) from either the cmake projects or the generated result in make or ninja format?
See http://clang.llvm.org/docs/LibTooling.html
Set CMAKE_EXPORT_COMPILE_COMMANDS=ON.
Ninja is actually able to print out commands to build all or specific target. And it does it extremely fast. As in on my machine in 0.033s for 1122 commands. It can print them either as shell commands or as compilation database and ycm has utility to use the compilation database.
It is important to note that the compdb ninja tool requires a rule name as argument. That does not seem to be mentioned in documentation.
The easiest is usually to do something in essence of CC=echo CXX=echo make and extract the arguments from it.
There's already an implementation of this in the clang_complete plugin, see the cc_args.py script at https://github.com/Rip-Rip/clang_complete/blob/master/bin/cc_args.py and documented in https://github.com/Rip-Rip/clang_complete/blob/master/doc/clang_complete.txt for more informations. If I'm not mistaken YCM can read .clang_complete files.
For example in clang_complete you run it like make CC='~/.vim/bin/cc_args.py gcc' CXX='~/.vim/bin/cc_args.py g++' -B
I'd not be surprised if YCM had a similar mechanism already available out of the box.
[EDIT] Yes it has, see https://github.com/Valloric/YouCompleteMe#c-family-semantic-completion-engine-usage and the "Clang's CompilationDatabase" support from the YCM documentation. Basically, either have make generate a file with the compilation flags for YCM to use or have clang generate a compilation database and have YCM use that.
I want to have something in CMake that will be executed whenever I enter make
add_custom_command(
OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/build_date.cc
PRE_BUILD
COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/mk_build_date.py
${CMAKE_CURRENT_BINARY_DIR}/build_date.cc
)
add_custom_target(build-date-xxx
ALL
DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/build_date.cc)
thats what I'm currently doing. unfortunately make build-date-xxx will generate the file only once.
even without the add_custom_target declaration the file is only build once.
the result should be something like this in GNU Make
.PHONY all:
echo "hallo welt"
all: foo.c bar.c
%.c:
touch $#
in that makefile whenever make is entered. since all is the first target it will always be invoked and the custom command echo "hallo welt" is actually executed.
Try using ADD_CUSTOM_TARGET and use the argument ALL in it.
Then make your main target dependent on this custom target.
Reverse your order... have a custom target with no dependencies (no DEPENDS) that generates your file, and add a custom command that depends on this target, mentions that it OUTPUTs the file, and doesn't actually do anything (e.g. COMMAND ${CMAKE_COMMAND} -E echo). Then mention the output file somewhere (presumably you have it as a source of a library or executable). (You can also use ALL for the custom target, but I'm assuming that some code object actually uses the output file, so you'd want said code object to depend on the output file.)
Ideally you'd want to refrain from modifying the file unless something actually changes, or else you won't ever get a no-op build. (How to do this is left as an exercise for the reader.)
I'm wanting to setup my CMakeLists.txt file so that it can generate the .clang_complete file required by the vim plugin clang_complete.
Ordinarily, you would do this by passing a parameter to the python script it supplies with the compiler and all of the parameters for compilation. Note that I am omitting the actual directory cc_args.py is in to save on space.
cc_args.py gcc test.c -o test -I~/IncludeDirs/
You can also do this during the make phase...
make CC='cc_args.py gcc' CXX='cc_args.py g++'
However, I am unsure of how to (if it is possible to) set this up within a CMakeLists.txt file. It's really annoying to have to type this in every time I want to setup clang_complete. The reason why I want to do it this way, is because I have multiple projects that I use a custom script to build the CMakeLists.txt file, so having to write a script for each one or manually place a generic one is a step I'd like to avoid.
I've tried a couple of things that have so far have come up with errors.
I've tried setting CMAKE_CC_COMPILER and CMAKE_CXX_COMPILER to lines similar to the first i.e. "cc_args.py g++". The errors that come up here say that It can't find the compiler (which is understandable).
The next thing I tried was setting the Compiler variables just to the cc_args.py and adding a flag for the actual compiler: suffice to say, that failed horribly. CMake said that it couldn't compile a test program (considering the script isn't a compiler, and the tests don't use the flags I set, I'm not surprised at this).
So without writing any other external scripts that require moving around, is there anyone that can think of a way that can do this?
The solution is to set the CXX environment variable before executing cmake. Something like that:
CXX="$HOME/.vim/bin/cc_args.py clang++" cmake ..
make
See http://www.guyrutenberg.com/2013/01/29/vim-creating-clang_complete-using-cmake/ for more details.
I know you said "without writing any other external scripts," but it seems like you just need a one-liner:
exec cc_args.py g++
And then set that file as your CMAKE_CXX_COMPILER. You could even use CMake's file() function to write the one-liner at build time if you don't want to have to distribute it.