The problem I'm having at the moment is that I simply wish to manage my list of source files by grabbing everything and removing the few odds and ends that I do not need. I was hoping that Cmake provided nice built-in tools for this.
So I might start with:
file(GLOB A "Application/*.cpp")
I feel like I want to create another list of files to be removed and I want to tell CMake: Remove from list A items that are in list B.
If this were Python I might do something like:
C = [f for f in A if f not in B]
I may have screwed that syntax up but I'm wondering if there is built-in support for managing these lists of files in a more elegant way?
Even if I could do something like my Python example, A is list of absolute paths so constructing B is clunky.
And why absolute paths anyway? It seems like this will break your build as soon as you relocate the source.
You can do that by using the list command with the REMOVE_ITEM option:
list(REMOVE_ITEM <list> <value> [<value> ...])
Have a look:
file(GLOB FOO *)
set (ITEMS_TO_REMOVE "item;item2;item3")
message(STATUS "FOO is ${FOO}")
list(REMOVE_ITEM FOO ${ITEMS_TO_REMOVE})
message(STATUS "FOO is now ${FOO}")
Keep in mind that the paths returned by file(GLOB) are absolute, you might want to build your list of items to remove by prepending ${CMAKE_CURRENT_LIST_DIR} to each one of them:
set (ITEMS_TO_REMOVE "${CMAKE_CURRENT_LIST_DIR}/item;
${CMAKE_CURRENT_LIST_DIR}/item2;
${CMAKE_CURRENT_LIST_DIR}/item3")
If you like Python, you can generate your list of source files with execute_process. There is also possiblity to work with lists.
But I would recommend you to "hardcode" your list of source files.
File command documentation states:
We do not recommend using GLOB to collect a list of source files from your source tree. If no CMakeLists.txt file changes when a source is added or removed then the generated build system cannot know when to ask CMake to regenerate.
Related
I have an AndroidStudio project with 'C' files in. I can compile and run as-is.
My native files are in
src/main/jni/aes
src/main/jni/libjpeg
src/main/jni/smuglib
I am trying to move the source to a location external to the Android studio project so that I can use it from several locations/projects to avoid copy/paste/mistake cycle.
I have defined the include path in CMakeLists.txt
include_directories(src/main/jni/aes src/main/jni/libjpeg src/main/jni/smuglib)
And have specified the files in the add_library command
add_library( # Sets the name of the library.
native-lib
# Sets the library as a shared library.
SHARED
# Provides a relative path to your source file(s).
src/main/jni/aes/aes.c
src/main/jni/smuglib/smuglib.c
.... etc
How do I set up a variable to refer to these paths, eg 'src/main/jni/aes' so that I can use it in both the include and in the source list?
I tried variations on
set(aes_src, src/main/jni/aes)
but uses of it as ${aes_src} either in the include path statement or in the source list give me all sorts of arcane errors which I am at a loss to understand.
I will generate some of these and include them if folk think it would help, but I am likely barking up the wrong kettle of fish with this approach.
Is there a better approach?
It is set(VAR_NAME item1 item2 item3). No commas needed.
Imagine a code generator which reads an input file (say a UML class diagram) and produces an arbitrary number of source files which I want to be handled in my project. (to draw a simple picture let's assume the code generator just produces .cpp files).
The problem is now the number of files generated depends on the input file and thus is not known when writing the CMakeLists.txt file or even in CMakes configure step. E.g.:
>>> code-gen uml.xml
generate class1.cpp..
generate class2.cpp..
generate class3.cpp..
What's the recommended way to handle generated files in such a case? You could use FILE(GLOB.. ) to collect the file names after running code-gen the first time but this is discouraged because CMake would not know any files on the first run and later it would not recognize when the number of files changes.
I could think of some approaches but I don't know if CMake covers them, e.g.:
(somehow) define a dependency from an input file (uml.xml in my example) to a variable (list with generated file names)
in case the code generator can be convinced to tell which files it generates the output of code-gen could be used to create a list of input file names. (would lead to similar problems but at least I would not have to use GLOB which might collect old files)
just define a custom target which runs the code generator and handles the output files without CMake (don't like this option)
Update: This question targets a similar problem but just asks how to glob generated files which does not address how to re-configure when the input file changes.
Together with Tsyvarev's answer and some more googling I came up with the following CMakeList.txt which does what I want:
project(generated)
cmake_minimum_required(VERSION 3.6)
set(IN_FILE "${CMAKE_SOURCE_DIR}/input.txt")
set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS "${IN_FILE}")
execute_process(
COMMAND python3 "${CMAKE_SOURCE_DIR}/code-gen" "${IN_FILE}"
WORKING_DIRECTORY ${PROJECT_BINARY_DIR}
INPUT_FILE "${IN_FILE}"
OUTPUT_VARIABLE GENERATED_FILES
OUTPUT_STRIP_TRAILING_WHITESPACE
)
add_executable(generated main.cpp ${GENERATED_FILES})
It turns an input file (input.txt) into output files using code-gen and compiles them.
execute_process is being executed in the configure step and the set_property() command makes sure CMake is being re-run when the input file changes.
Note: in this example the code-generator must print a CMake-friendly list on stdout which is nice if you can modify the code generator. FILE(GLOB..) would do the trick too but this would for sure lead to problems (e.g. old generated files being compiled, too, colleagues complaining about your code etc.)
PS: I don't like to answer my own questions - If you come up with a nicer or cleaner solution in the next couple of days I'll take yours!
So I am writing a CMake module to find some libraries which is being used a lot in our company. These libraries all have different versions and are such a mess here. In a certain library, even the name of header files and binary files don't match. So I am writing a CMake script to handle all the problems of finding each library once and for all. What I have in my mind is to write something like how we find boost packages but include the version of each component as well. Something like this:
find_package(OrgName COMPONENTS librarya-1.4.3 libraryb-2.3.1 libraryc-3.6.0)
So I created a FindOrgName.cmake file and iterated on the requested components, then I processed the string which is passed and gained the library name along with its version information something like this (never mind the difference between include and binary files):
IF(OrgName_FIND_COMPONENTS)
FOREACH(comp ${OrgName_FIND_COMPONENTS})
SET(OrgName_${comp}_FOUND 0)
STRING(FIND ${comp} "-" dashind REVERSE)
STRING(LENGTH ${comp} length)
STRING(SUBSTRING ${comp} 0 ${dashind} name)
MATH(EXPR s "${dashind}+1")
MATH(EXPR l "${length}-${dashind}-1")
STRING(SUBSTRING ${comp} ${s} ${l} version)
SET(OrgName_${name}_INCLUDE_DIR "/usr/local/include/OrgName/${comp}/")
find_library(OrgName_${comp}_LIBRARIES NAMES "${comp}" HINTS "/usr/lib")
IF(OrgName_${comp}_INCLUDE_DIR AND OrgName_${comp}_LIBRARIES)
SET(OrgName_${comp}_FOUND 1)
ENDIF()
IF(NOT OrgName_${comp}_FOUND AND OrgName_FIND_REQUIRED_${comp})
MESSAGE(FATAL_ERROR "OrgName ${comp} not available.")
ENDIF()
SET (OrgName_INCLUDE_DIR ${OrgName_INCLUDE_DIR} ${OrgName_${comp}_INCLUDE_DIR})
SET (OrgName_LIBRARIES ${OrgName_LIBRARIES} ${OrgName_${comp}_LIBRARIES})
ENDFOREACH()
ENDIF()
Now here is the problem, imagine someone didn't enter the version part in components names. I want to search for the versions which he has installed (assume the path to library is always the same) and use the last version it can find, so I have to search for the files which their name contains the library name (${name}). First of all how can I do this? Second, Am I doing things right? I mean is there an easier way to do this task?
OK, after a lot of searching and getting exhausted I finally found a solution. I just need to use the following command:
file(GLOB files "Mylib*")
Which will create a list named files and adds each file that its name matches the pattern "Mylib*" to it. I really don't know why they didn't implement it in find_file command but never mind, I'll put it here in case anyone got confused like me.
I am using CMake to build a simple C++ project, hereafter named P. The structure of P is quite simple:
P/src/
P/src/package1
P/src/packege2
P/src/...
P/src/main-app
I would like to collect the libraries in package1, package2, ... in a variable called P_LIBS.
In a first attempt, I tried to collect the libraries available in package1, package2, ... in the variable called P_LIBS initially set in the src/CMakeLists.txt file. However, the updates to P_LIBS made in the CMakeLists.txt of the subfolders are not propagated to the parent folder.
I would rather not write a list of libraries in the main CMakeLists.txt file. I would rather modify such variable while moving in the directory tree.
After a search on the internet I could not find any valid suggestion. If I look at the various Find files, I only see long listings of libraries in their main CMakeLists.txt file.
Is there a way to do what (I hope) I explained above?
Thanks to sakra's link I was able to 'propagate' names up to the parent folder. However, the names I add to the P_LIBS variable are later interpreted as 'library' names, not as reference to CMake targets. In other words, if
P_LIBS = {a, b}
the 'a' and 'b' are interpreted as the library names, i.e. CMake generates:
gcc [...] -l a -o exe
instead of
gcc [...] /path/to/a.o -o exe
(.o or other extensions)
You are propably constructing the targets list as a string, try to make them a list instead. For example:
# in package1/CMakeLists.txt
set(P_LIBS ${P_LIBS} a b PARENT_SCOPE)
I feel a little stupid right now. After recently converting a few smaller projects to use CMake, I decided to also get rid of a few "Platform_Config.h" files. These files contain a few preprocessing directives like #define USE_NEW_CACHE and control compilation.
How would I 'convert' these defines to be controlled with CMake? Ideally by using these "cache" variables the user can easily edit.
There are two options. You can use the add_definitions method to pass defines as compiler flags: E.g. somewhere in your projects cmakelists.txt:
add_definitions( -DUSE_NEW_CACHE )
CMake will make sure the -D prefix is converted to the right flag for your compiler (/D for msvc and -D for gcc).
Alternatively, check out configure_file. It is more complex, but may be better suited to your original approach with a Platform_Config file.
You can create an input-file, similar to your original Platform_Config.h and add "#cmakedefine" lines to it.
Let's call in Platform_Config.h.in:
// In Platform_Config.h.in
#cmakedefine USE_NEW_CACHE
// end of Platform_Config.h.in
When then running
configure_file( ${CMAKE_SOURCE_DIR}/Platform_Config.h.in ${CMAKE_BINARY_DIR}/common/Platform_Config.h )
it will generate a new Platform_Config file in your build-dir. Those variables in cmake which are also a cmakedefine will be present in the generated file, the other ones will be commented out or undefed.
Of course, you should make sure the actual, generated file is then correctly found when including it in your source files.
option command might provide what you are looking for.
use it with the COMPILE DEFINITIONS property on the target and i think you are done.
To set the property on the target, use the command set target properties
option(DEBUGPRINTS "Prints a lot of debug prints")
target(myProgram ...)
if(DEBUGPRINTS)
set_target_properties(myProgram PROPERTIES COMPILE_DEFINITIONS "DEBUGPRINTS=1")
endif()
edit:
The option i wrote in the example shows up as a checkbox in the CMake GUI.
In case you want to set defines per target: Since 2.8.11 you can use target_compile_definitions.
In earlier versions you probably don't want to use set_target_properties as is, since it overwrites any defines you set previously. Call get_target_property first instead, then merge with previous values. See add_target_definitions here.
Use target_compile_options. Do not quote your define or it not be detected as a define. CMake parses off the /define and adds the actual define to the DefineConstants section of the csproj, if there are quotes it will put the entire quoted string in the AdditionalOptions section of the csproj.
An example from one of my projects that uses generator expressions:
target_compile_options( ${LIBRARY_NAME} PRIVATE
$<${IS_ART_ITERATION_BUILD}:/define:ART_ITERATION_BUILD>
)
An example without generator expressions:
target_compile_options( ${LIBRARY_NAME} PRIVATE
/define:GRAPHICS_VULKAN
)