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How to call a CMake function from add_custom_target/command?
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Closed 5 years ago.
I want to have a cmake target that updates a specific file.
I tried following but it seems that I cannot put all what I want into a custom target.
ADD_CUSTOM_TARGET(update
file(READ "file.h" myFile)
string(REPLACE "originalString" "newString" myFile"${myFile}"))
)
I'm quite new to cmake so I may be missing something basic. How could I update the file on request ?
What I personally use for this type of problem is use configure_file. Essentially, you can make what you consider a template file and wrap variable names in the files.
Example.h.template
Here is my #VAR#
Then if you have VAR defined in your CMake project, it will replace VAR in your destination.
configure_file(<input> <output> NEWLINE_STYLE WIN32)
If input (your template) is modified, CMake will be re-run to keep your file up to date. So in your cmake you can
set(VAR "program")
configure_file("Path/To/Example.h.template" "Path/To/File.h" NEWLINE_STYLE [UNIX|DOS|WIN32|LF|CRLF])
The result should be:
File.h
Here is my program
Related
In the build process, I set directories where I gather the build output of different sub-projects. The directories are set as :
set( CMAKE_RUNTIME_OUTPUT_DIRECTORY_DEBUG "${CMAKE_CURRENT_LIST_DIR}/../build/bin/debug" )
set( CMAKE_RUNTIME_OUTPUT_DIRECTORY_RELEASE "${CMAKE_CURRENT_LIST_DIR}/../build/bin/release" )
Now, I'd like to copy some files (a directory of qt plugins) to that directory dependent on the configuration which it is built for.
I tried:
# copy qt plugins
add_custom_command( TARGET mytarget POST_BUILD
COMMAND ${CMAKE_COMMAND} -E copy_directory
"${QT_DIR}/../../../plugins"
"${$<UPPER_CASE:CMAKE_RUNTIME_OUTPUT_DIRECTORY_$<CONFIG> >}/plugins"
COMMAND_EXPAND_LISTS)
thus, I try to build a string that equals the variable name and then try to expand that as described here: CMake interpret string as variable. In other words: I would like to have a generator expression that evaluates to the content of CMAKE_RUNTIME_OUTPUT_DIRECTORY_DEBUG or CMAKE_RUNTIME_OUTPUT_DIRECTOR_RELEASE dependent on the current build configuration.
However running cmake with the statement above results in an error:
"CMakeLists.txt:112: error: Syntax error in cmake code at [..] when parsing string ${$<UPPER_CASE:CMAKE_RUNTIME_OUTPUT_DIRECTORY_$<CONFIG> >}/plugins Invalid character ('<') in a variable name: '$'
So my question is, how can I use a generator-expression to access the corresponding variable? (Bonus question: is there another/better way to achieve the same goal?)
So my question is, how can I use a generator-expression to access the corresponding variable?
You cannot. There is currently (CMake <=3.23) no way to expand a variable whose name is determined by the value of a generator expression.
Bonus question: is there another/better way to achieve the same goal?
Yes, and you are almost there! You can use $<TARGET_FILE_DIR:...>:
add_custom_command(
TARGET mytarget POST_BUILD
COMMAND
${CMAKE_COMMAND} -E copy_directory
"${QT_DIR}/../../../plugins"
"$<TARGET_FILE_DIR:mytarget>/plugins"
VERBATIM
)
This works because TARGET_FILE_DIR evaluates to the actual directory containing the executable or library file for mytarget, no matter the active configuration, property values, etc.
Docs: https://cmake.org/cmake/help/latest/manual/cmake-generator-expressions.7.html#genex:TARGET_FILE_DIR
CMAKE_RUNTIME_OUTPUT_DIRECTORY_<CONFIG> is already relative to the binary directory so you should not try to compute the binary directory in its definition. Also, it supports generator expressions. Thus, the following will be much more robust:
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "bin/$<LOWER_CASE:$<CONFIG>>"
CACHE STRING "Common output directory for runtime artifacts")
This has a bunch of concrete benefits:
No need to set CMAKE_RUNTIME_OUTPUT_DIRECTORY_DEBUG or CMAKE_RUNTIME_OUTPUT_DIRECTORY_RELEASE
This will work for MinSizeRel and RelWithDebInfo, plus any custom configurations one might add down the line.
Since it's defined as a cache variable, it can be overridden for debugging / working around name clashes, etc.
A bit more context for (3): most CMAKE_* variables are intended to be either read-only or user-configurable (i.e. at the command line, from the GUI, etc.). Overriding their defaults via set(CACHE) is a polite compromise. A notable exception to this rule is the collection of Qt codegen flags (CMAKE_AUTO{MOC,RCC,UIC}). These must typically be set for the build to produce usable binaries.
I have such a requirement. I want to modify my source file according to the configuration file in the cmake stage. Is there a good way?
configure_file command is your friend.
First you create a template file filled with strings line ${MY_VAR} (called foo.ext.in by convention) and then pass into as the argument of configure_file. During configuration step, CMake will generate foo.ext file from your template, substituting any ${VARS} with corresponding values from CMake code scope.
I would like to have a command or option to list all the modified cache variables of the current build configuration. While cmake -L[AH] is nice, it is also quite overwhelming and doesn't show which are non-default values.
There seems to be a variable property MODIFIED that sounds exactly like what I'm looking for - but the documentation is not very reassuring:
Internal management property. Do not set or get.
This is an internal cache entry property managed by CMake to track interactive user modification of entries. Ignore it.
This question also didn't help: CMAKE: Print out all accessible variables in a script
There are so many ways you could change or initialize variables in CMake (command line, environment variables, script files, etc.) that you won't be able to cover them all.
I just came up with the following script that covers the command line switches. Put the following file in your CMake project's root folder and you get the modified variables printed:
PreLoad.cmake
set(_file "${CMAKE_BINARY_DIR}/UserModifiedVars.txt")
get_directory_property(_vars CACHE_VARIABLES)
list(FIND _vars "CMAKE_BACKWARDS_COMPATIBILITY" _idx)
if (_idx EQUAL -1)
list(REMOVE_ITEM _vars "CMAKE_COMMAND" "CMAKE_CPACK_COMMAND" "CMAKE_CTEST_COMMAND" "CMAKE_ROOT")
file(WRITE "${_file}" "${_vars}")
else()
file(READ "${_file}" _vars)
endif()
foreach(_var IN LISTS _vars)
message(STATUS "User modified ${_var} = ${${_var}}")
endforeach()
This will load before anything else and therefore can relatively easily identify the user modified variables and store them into a file for later reference.
The CMAKE_BACKWARDS_COMPATIBILITY is a cached variable set by CMake at the end of a configuration run and therefor is used here to identify an already configured CMake project.
Reference
CMake: In which Order are Files parsed (Cache, Toolchain, …)?
I have a project that uses some third party libraries. So each time I setup this project with CMake, I have to set each entry (path of the third party library) on the GUI of CMake. I improve this by making CMake script guess the path by this script (learn this technique from OGRE):
# Guess the paths.
set( OGRE_SOURCE "${CMAKE_CURRENT_SOURCE_DIR}/Dependencies/Ogre" CACHE STRING "Path to OGRE source code (see http://www.ogre3d.org/tikiwiki/tiki-index.php?page=CMake+Quick+Start+Guide)" )
So each time I setup with CMake, it will automatic fill the entry OGRE_SOURCE. But that doesn't enough. If the Ogre source is not in the path
"${CMAKE_CURRENT_SOURCE_DIR}/Dependencies/Ogre"
, then I have to open and edit the CMake script or I have to edit the entry on the GUI of CMake. I find that pretty inconvenient, especially when you link to a lot of third party libraries.
So I want to use another technique: preset settings for entries from file - CMake reads the presets from file PresetEntries.txt (that I make) and apply the these presets on the entries (It's a lot quicker to edit the path in text file than on the GUI of CMake).
Here my idea about this preset file: PresetEntries.txt
OGRE_SOURCE=E:/Source/ogre
I found that CMake can read a text file, but if I use this, I have to do string manipulations.
CMake has the file CMakeCache.txt to save the settings on the CMake GUI, but I want it to be simple: it should only has the preset settings that need to be pre-set.
So I wonder if CMake support this preset settings for entries from file.
Edit:
So I read this question and see that CMake can set config from file, but this require to fire cmake with the -C mysettings.cmake, but I wanna it to be automatically with CMake GUI - just edit the file and hit generate button in CMake GUI. So I wanna make this question more specific:
In my CMakeLists.txt should have script like this:
# Guess the paths.
#I wanna have this function from C++
#https://msdn.microsoft.com/en-us/library/windows/desktop/ms724353%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396
GetPrivateProfileString("OGRE", #lpAppName
"OGRE_SOURCE", #lpKeyName
"${CMAKE_CURRENT_SOURCE_DIR}/Dependencies/Ogre", #lpDefault
OGRE_SOURCE_VAR,#lpReturnedString
MAX_PATH, #nSize, may be can reduce this variable
"LibPath.ini") #lpFileName
set( OGRE_SOURCE "${OGRE_SOURCE_VAR}" CACHE STRING "Path to OGRE source code" )
In the file LibPath.ini
[OGRE]
OGRE_SOURCE = "E:/Source/ogre"
So the user can choose to either use the ini file or not.
I don't know if there any way I can use a function that similar to function GetPrivateProfileString (of C++) in CMake.
Thanks for reading
The external libraries should be included by one of the following commands
find_package(ttnlib REQUIRED HINTS /usr/local/lib/cmake)
include_directories(${ttnlib_INCLUDE_DIR})
set(EXTRA_LIBS ${EXTRA_LIBS} ${TTNLIB_LIBRARY})
or
find_library(MY_EXTERNAL_LIB name COOLSTUFF libCOOLSTUFF libCOOLSTUF.so hints /usr/local/lib)
The search for the external packages and libraries should only be necessary for the first run of cmake.
I can't find the function to read the ini file, so what I can do is create a simple function that read simple txt file for myself.
I declare the function in 1 file for other file use it
"\CMake\Dependencies\CommonFunc.cmake"
#------------Define function Read file------------
macro( readSettingFile KEY DEFAULT_RESULT STRING_RESULT_OUT)
unset(STRING_RESULT)
# Read the file
file( READ "${CMAKE_SOURCE_DIR}/LibPath.txt" LIB_PATH_STR )
# Set the variable "Esc" to the ASCII value 27 - basically something
# which is unlikely to conflict with anything in the file contents.
string(ASCII 27 Esc)
# Turn the contents into a list of strings, each ending with an Esc.
# This allows us to preserve blank lines in the file since CMake
# automatically prunes empty list items during a foreach loop.
string(REGEX REPLACE "\n" "${Esc};" LIB_PATH_LINES "${LIB_PATH_STR}")
foreach(LINE ${LIB_PATH_LINES})
if("${LINE}" MATCHES "${KEY}")
#remove the key, leave the content untouch
string(REPLACE "${KEY}" "" STRING_RESULT ${LINE})
# Swap the appended Esc character back out in favour of a line feed
string(REGEX REPLACE "${Esc}" "" STRING_RESULT ${STRING_RESULT})
endif()
endforeach()
if("${STRING_RESULT}" STREQUAL "")
set( STRING_RESULT ${DEFAULT_RESULT} )
endif()
#message( STATIC "---GTA Sa-----" "[${STRING_RESULT}]" )
endmacro()
(I need the help from this answer to write this function :p)
Here is how I use
For example: "\CMake\Dependencies\Ogre.cmake"
#include common functions
include( CMake/Dependencies/CommonFunc.cmake )
#---------------Guess the paths.----------------------
#----Set OGRE_SOURCE
readSettingFile( "OGRE_SOURCE="
"E:/Source/ogre"
STRING_RESULT
)
set( OGRE_SOURCE "${STRING_RESULT}" CACHE STRING "Path to OGRE Source" )
#----Set OGRE_BINARIES
readSettingFile( "OGRE_BINARIES="
"E:/Source/_build/ogre"
STRING_RESULT
)
set( OGRE_BINARIES "${STRING_RESULT}" CACHE STRING "Path to OGRE's build folder generated by CMake" )
Here is the setting file
"\LibPath.txt"
OGRE_SOURCE=E:/Source/ogre
OGRE_BINARIES=E:/Source/_build/ogre
I'm trying to make another guy's research code reproducible, so that others don't have the same trouble I'm having right now. But, I'm lacking the experience with cmake for that. Here is what I could do after reading the docs:
In the same folder as my CMakeLists.txt I have a file called io_utils.h with a ROOT_PATH variable whose value is VALUE_ROOT_PATH.
I want to replace that string with the value of the file's current directory. So I tried to add the following to CMakeLists.txt:
# Set ROOT_PATH in io_utils.h
FIND_PATH(BUILD_PATH CMakeLists.txt . )
FILE(READ ${BUILD_PATH}io_utils.h IO_UTILS)
STRING(REGEX REPLACE "VALUE_ROOT_PATH" "${BUILD_PATH}" MOD_IO_UTILS "${IO_UTILS}" )
FILE(WRITE ${BUILD_PATH}io_utils.h "${MOD_IO_UTILS}")
I tried to make and install that but it is not working, the file isn't changed. What's wrong with what I did?
I suggest a different approach using the configure_file cmake macro. First, you create a template file that references any variables you plan to set in cmake, then the macro substitutes the actual value in place of the variable. For example, let's say we have a template file io_utils.h.in that looks something like this:
const char* ROOT_PATH = "${BUILD_PATH}";
In your CMakeLists.txt, you can do something like this:
configure_file( io_utils.h.in io_utils.h )
When you run cmake, it will use the first file as a template (io_utils.h.in here) to generate the second file (called io_utils.h here) with the value substituted in:
const char* ROOT_PATH = "/path/to/CMakeLists.txt";
By the way, CMake has a built-in variable that references the directory with the top-level CMakeLists.txt called CMAKE_SOURCE_DIR. Try replacing BUILD_PATH above with this variable.
In this case it seems to be a lot easier to define a macro and let the preprocessor do the job:
add_definition(ROOT_PATH ${VALUE_ROOT_PATH})