I'm trying to use cmake (on Linux with GNU make and g++) to build a project with two sub-directories: MyLib and MyApp. MyLib contains source for a static library; MyApp needs to link against that library. I'm trying to build on Linux with generated makefiles using the following CMakeLists.txt:
cmake_minimum_required (VERSION 2.6)
project (MyProj)
include_directories (MyLib)
file(GLOB MyLibSrc MyLib/*.cpp)
add_library(MyLibrary STATIC ${MyLibSrc})
file(GLOB MyAppSrc MyApp/*.cpp)
add_executable(MyApplication ${MyAppSrc})
target_link_libraries(MyApplication MyLibrary)
This 'almost' works. It fails at link time because while it generates libMyLibrary.a - it is in the root. When I add:
link_directories(${MyProj_BINARY_DIR})
it makes no difference.
I've got a few (inter-linked) questions:
What's the best way to coerce cmake into building my library and executable into a 'staging directory' — say MyStage — to keep targets separate from source?
How do I convince cmake to link the application against the library?
If I wanted to build a debug and a release version, what's the best way to extend my cmake scripts to do this — making sure that the debug application links against the debug library and the release application against the release library?
I'm a relative newcomer to cmake. I've read what I can find on the web, but find myself struggling to get my library to link with my executable. This sort of a configuration, to my mind, should be quite common. An example from which to crib would be very helpful, but I've not found one.
Well, it is better to read this example and do exactly as suggested.
cmake_minimum_required (VERSION 2.6)
project (MyProj CXX)
add_subdirectory(MyLib)
add_subdirectory(MyApp)
Then for each subdirectory specified, CMakeLists.txt files are created
MyLib\CMakeLists.txt
file(GLOB SRC_FILES *.cpp)
add_library(MyLib ${SRC_FILES})
MyApp\CMakeLists.txt
file(GLOB SRC_FILES *.cpp)
add_executable(MyApp ${SRC_FILES})
target_link_libraries(MyApp MyLib)
Use "out of the source build". Make a directory used only for build and while in it, call
cmake <path to the sources, it may be relative>
Either use
link_directories(${MyProj_BINARY_DIR}/MyLib)
or make CMakeLists.txt in each subdirectory - that would be better for project larger than very small.
This is a bit tricky, check out CMAKE_BUILD_TYPE in the docs (you can set it and/or "if" by it). You can also set it from command line:
cmake -DCMAKE_BUILD_TYPE=Debug
I've discovered the 'optimal' solution to (1)... so, thought I should post it here:
SET(CMAKE_ARCHIVE_OUTPUT_DIRECTORY MyStage)
SET(CMAKE_RUNTIME_OUTPUT_DIRECTORY MyStage)
The thing that confused me previously is that static libraries are not considered a LIBRARY by Cmake - they're considered to be ARCHIVEs.
Do not add libraries and executables in the root Cmakelists.txt. Add these libraries and executables in Cmakelists.txt of subdirectories.
Related
I'm trying to include SFML as a dependency in my CMake project, and it compiles SFML fine, but I can't figure out how to link it.
Here's my CMakeLists.txt, with annotated comments:
cmake_minimum_required(VERSION 3.9.1)
set(CMAKE_LEGACY_CYGWIN_WIN32 1)
set (CMAKE_CXX_STANDARD 11) # Set C++11
project(CHIP8)
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib) # static library
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib) # dynamic library
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin) # executables
set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/modules" ${CMAKE_MODULE_PATH})
# Include SFML
add_subdirectory(${CMAKE_SOURCE_DIR}/dep/SFML)
include_directories(${CMAKE_SOURCE_DIR}/dep/SFML/include)
#Include where to find headers
include_directories(./src)
include_directories(./src/headers)
# Do a GLOB search, and add them to executable
set(EXECUTABLE_NAME "CHIP8")
file(GLOB SRC_FILES
"src/headers/*.h"
"src/*.cpp"
)
add_executable(${EXECUTABLE_NAME} ${SRC_FILES})
target_link_libraries(${EXECUTABLE_NAME} SFML) #Here is where the problem lies!
As you can see, I'm adding the subdirectory ./dep/SFML so it compiles with its own CMakeLists. Including the headers too on the next line, which VSCode picks up.
However, I'm having trouble on the last line: target_link_libraries. It can't find sfml SFML or SFML2. Therefore, I'm not sure how to link it.
Anyone have any idea?
Thanks.
SFML is not a single library, but a set of libraries, each of which corresponds to some component. For component named
<component-name>
the library target is named
sfml-<component-name>
When use SFML in your code, you should know which SFML component(s) you use (see SFML docs/tutorials), and link with corresponded libraries:
# Assuming you use "graphics" and "system" SFML components
target_link_libraries(<your-executable> sfml-graphics sfml-system)
Note, that such targets' naming is not officially documented, so it can be changed in the future.
Preferred way for link with SFML is to install it before (or during) configuring your project, and use
find_package(SFML REQUIRED COMPONENTS graphics system)
include_directories(${SFML_INCLUDE_DIR})
target_link_libraries(<your-executable> ${SFML_LIBRARIES})
I am trying to use CMake to build a library (which in turn links to other libraries built via CMake). I am having a couple of issues with this process and would love to have some guidance.
For the library, I have a CMakeLists.txt which essentially has
set(SRC srcfile1.cpp srcfile2.cpp)
set(HEADERS srcfile1.h srcfile2.h)
add_library(myLib ${SRC} ${HEADERS})
INSTALL(FILES ${HEADERS} DESTINATION “include/myLib”)
For a “Unix Makefiles” generator, with cmake command
cmake -DCMAKE_INSTALL_PREFIX=. -DCMAKE_BUILD_TYPE=debug -G “Unix Makefiles” ..
I get an appropriate debug library libMyLib.a in build/src. For a release build type, a release build of libMyLib.a is placed in build/src
However, for an Xcode generator, the library is placed in src/Debug. The issues I am facing here are
a. Doing an Archive in Xcode doesn’t seem to have any effect. I don’t see a corresponding Release library being created anywhere
b. I also have a myLibTests target (which uses googles gtest) which is defined in it’s CMakeLists.txt as
set(SRC myTest.cpp)
add_executable(myLibTests ${SRC})
add_dependencies(myLibTests myLib gtest)
set(gTestLib External/src/gTestLib)
target_link_libraries(myLibTests myLib gTestLib)
When the cmake generator is “Unix Makefiles” myLibTests build, links and runs fine. gTestLib is placed in External/src/gtest-build/. But, when it is “Xcode”, it can’t find the gTest libraries. because, the library is placed in External/src/gTestLib/Debug(or Release) as the case may be (and the above path set in CMakeLists.txt is no longer valid). I am not sure how to set it’s path appropriately in the above set statement.
Since, debug/release is controlled in Xcode (and the configure process in CMake is unaware of this), I assume there isn’t a way to separate the release/debug builds of the gTestLib and also have CMake configure Xcode to pick up the appropriate version while building myLib i.e if I do a debug build of myLib it also does a debug build of gTest and links to it (similar for release builds)? Alternatively, is it possible to configure Xcode to place both the Debug and Release builds in the same location (and then hardcode it’s path above)? What would be the best way of configuring this?
Thanks
I am trying to use CMake with Qt and LuaJIT that will run on Visual Studio 2012. I managed somehow to run Qt, but i don't know how to add LuaJIT library to project. I am using source of LuaJIT cloned from http://luajit.org/git/luajit-2.0.git, which is build by running .bat file.
I dont care that LuaJIT will be build by CMake, i just need to link library and add headers to project.
I removed lib folder from my project... Is not worth troubles to have dependancies coupled with project whitout cmake file :D
My project hierarchy is:
+lib
-luajit-2.0
+src
-my sources
+ui
-ui files
-CMakeLists.txt
And CMakeLists.txt file looks like this:
cmake_minimum_required(VERSION 2.8.12)
set(PROJECT "Grapedit")
project(${PROJECT})
# Qt Stuff
set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOMOC ON)
find_package(Qt5Widgets REQUIRED)
set(SOURCE_FILES
src/main.cpp
src/mainwindow.h
src/mainwindow.cpp
)
set(UI_FILES
ui/mainwindow.ui
)
source_group("UI Files" FILES ${UI_FILES})
qt5_wrap_ui(UI_HEADERS ${UI_FILES})
source_group("Generated UI Headers" FILES ${UI_HEADERS})
add_executable(${PROJECT} ${SOURCE_FILES} ${UI_HEADERS} ${UI_FILES})
qt5_use_modules(${PROJECT} Widgets)
My solution
So it is finally working and I made couple of newbie mistakes... :)
I will write them down for others:
didn't know what is find module... This will search environment and set up locations of libraries or flag that it didn't find them. Since LuaJIT is compatible with Lua51 you can use find_package(Lua51).
Your libraries must be some way visible to CMake. On Windows simplest way is to add them to PATH variable. Or you can add path of your libraries to CMake variable CMAKE_PREFIX_PATH. Open find module, for example FindLua51.cmake and you will see how must be your library organized. On windows I've must installed LuaJIT manualy - created LuaJIT folder and I've put *.h files to include subfolder, *.dll to bin subfolder and *.lib to lib subfolder. Then add bin folder to PATH and set LUA_DIR to LuaJIT folder.
use include_directories on include folder
then you must link libraries target_link_libraries, but after add_executable!
My CMakeLists.txt file:
cmake_minimum_required(VERSION 2.8.12)
# Declare project variables...
set (PROJECT "Grapedit")
set (
SOURCE_FILES
src/main.cpp
src/mainwindow.h
src/mainwindow.cpp
)
set(UI_FILES
ui/mainwindow.ui
)
# Set project name
project(${PROJECT})
# Include Lua directories
include_directories(${LUA_INCLUDE_DIR})
# Qt Stuff
set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOMOC ON)
# Find packages...
# Will find also LuaJIT, but must be named same as Lua51 and installed into directories
find_package(Lua51)
# Find Qt modules, every module separately
find_package(Qt5Widgets REQUIRED)
# Create nice groups in IDEs
source_group("UI Files" FILES ${UI_FILES})
source_group("Generated UI Headers" FILES ${UI_HEADERS})
# Use Qt UI files
qt5_wrap_ui(UI_HEADERS ${UI_FILES})
# Create executable
add_executable (
${PROJECT}
${SOURCE_FILES}
${UI_HEADERS}
${UI_FILES}
)
# Link libraries...
# Must be after executable is created!
# Link Qt modules
qt5_use_modules (
${PROJECT}
Widgets
)
# Link Lua
target_link_libraries(${PROJECT} ${LUA_LIBRARIES})
# Will not show new windows prompt when running program
if (MSVC)
set_target_properties(${PROJECT} PROPERTIES
WIN32_EXECUTABLE YES
LINK_FLAGS "/ENTRY:mainCRTStartup"
)
endif ()
You are missing the actual linkage which you can amend with the following statement:
target_link_libraries(${PROJECT} luajit-5.1)
For sure, it would be even better if this lua jit could have a cmake find module, or config/version file depending on its exact build system.
You could grab the find module from here:
https://github.com/brimworks/lua-zlib/blob/master/cmake/Modules/FindLuaJIT.cmake
Then you could link against it as follows:
target_link_libraries(${PROJECT} ${LUA_LIBRARIES})
You can see that it would become more dynamic this way rather than hard-coding the exact name. The details for figuring out that would be left with the find module.
Note that you would probably need to use the corresponding variables for the header inclusion then as follows:
include_directories(${LUA_INCLUDE_DIR})
This will take care of automatically finding the include directory, respectively, without you hard-coding it.
You would also need to add the following line into your CMakeLists.txt:
set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
and you need to place the downloaded find module into a "cmake" subfolder.
Please refer to the following page for further details about this topic in general:
CMake:How To Find Libraries
I have an existing project (wvdial) that has a working makefile. I'm trying to integrate it into our main build process which uses CMake. Can anyone advise on how to do this? I made an attempt below based on some of the other projects we build but the makefile is never called. All I want to do is call the makefile for wvdial and include the binary in the .deb package we build.
cmake_minimum_required(VERSION 2.6)
SET(COMPONENT_NAME roots-vendor-wvdial)
SET(DEBIAN_PACKAGE_VERSION 1.6.1)
SET(WVDIAL_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
SET(WVDIAL_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
SET(WVDIAL_INSTALLED ${CMAKE_CURRENT_BINARY_DIR})
ADD_CUSTOM_TARGET(
wvdial ALL
DEPENDS ${WVDIAL_INSTALLED}
)
IF (${ROOTS_TARGET_ARCHITECTURE} STREQUAL "armhf")
SET(TARGET_FLAG "--host=arm-linux-gnueabihf")
ENDIF()
ADD_CUSTOM_COMMAND(
WORKING_DIRECTORY ${WVDIAL_BINARY_DIR}
OUTPUT ${WVDIAL_INSTALLED}
COMMAND env CXXFLAGS=${ROOTS_COMPILER_FLAGS} ./configure ${TARGET_FLAG} ${ROOTS_HOST_OPTION}
COMMAND make
COMMENT "Building wvdial"
VERBATIM
)
INSTALL(
FILES ${CMAKE_CURRENT_BINARY_DIR}/wvdial
DESTINATION usr/local/bin
COMPONENT ${COMPONENT_NAME}
PERMISSIONS OWNER_EXECUTE OWNER_READ OWNER_WRITE GROUP_EXECUTE GROUP_READ WORLD_EXECUTE WORLD_READ
)
DEFINE_DEBIAN_PACKAGE(
NAME ${COMPONENT_NAME}
CONTROL_TEMPLATE ${CMAKE_CURRENT_SOURCE_DIR}/debian/control
CHANGELOG_TEMPLATE ${CMAKE_CURRENT_SOURCE_DIR}/debian/changelog
)
Take a look at the ExternalProject module.
This will add a dummy target to your CMake project that is responsible for building the dependency. The command is quite complex and supports a lot of stuff that you probably won't need in your case. Kitware (the company behind CMake) did a nice post called Building External Projects with CMake 2.8 a while back explaining the basic use of that command.
I'm a learning c++ developer writing a game initially on the Mac platform using XCode, but now moving to cross platform by leveraging CMake. So far I can get it compiled on my ickle linux netbook and I'm putting together a dev environment on this machine for on the go coding. However I'm finding that gcc recompiles every file whenever I make a change. Clearly I need some additional configuration to the CMakeLists.txt . My current one is very simple. Like so;
cmake_minimum_required (VERSION 2.8)
set (source
Creature.cpp
DisplayManager.cpp
Engine.cpp
EngineState.cpp
Entity.cpp
GameWorld.cpp
GfxSFML.cpp
Item.cpp
Map.cpp
Position.cpp
Projectile.cpp
ScreenTile.cpp
SquadAI.cpp
Terrain.cpp
UIButton.cpp
UICharPanel.cpp
UIView.cpp
Utility.cpp
Weapon.cpp
fov.cpp
main.cpp
)
find_package (OpenAL)
find_package (OpenGL)
find_package (SFML)
set(CMAKE_CXX_FLAGS "-g -Wall -pg")
add_executable (tractionedge ${source})
target_link_libraries(tractionedge ${SFML_LIBRARY} ${OPENGL_LIBRARY} ${OPENAL_LIBRARY})
I've concentrated so far on C++ as a language rather than build systems by sticking with XCode for everything. My knowledge of Autotools (make?) and Gcc is very limited. How do I have gcc only recompile the changed source?
Are you rerunning cmake every time? If you just modify one source file, you should be able to simply rerun make, and it should rebuild just the one object file before linking. If you rerun cmake, it might mark all of the source files dirty and rebuild everything.
Only rerun cmake if you change the actual list of source files being used, or other major changes like that.
Rebuilding only the modified sources SHOULD be the default behavior. Of course if you change a central header included by nearly all dependent cpp files it'll trigger a nearly complete rebuild. Look at what happens if you only modify one cpp file (adding a comment or alike), if more than that compilation unit is compiling then I propose you to invest more time investigating it eventually giving you my EMail to have a deeper look at the configuration.
Another possibility is that you are compiling under windows and using a 2.8 cmake that has a bug regarding this. Look at a 2.9 version to see if that defect is away then: http://www.mail-archive.com/cmake#cmake.org/msg24876.html
I would rewrite your CMakeLists.txt using glob (maybe move the files in a "src" directory if you have other *.cpp files around) and give your project a name (this sets some important variables):
cmake_minimum_required (VERSION 2.8)
project(TRACTION)
file (GLOB TRACTION_SOURCES *.cpp)
find_package (OpenAL)
find_package (OpenGL)
find_package (SFML)
set(CMAKE_CXX_FLAGS "-g -Wall -pg")
add_executable (tractionedge ${TRACTION_SOURCES})
target_link_libraries(tractionedge ${SFML_LIBRARY} ${OPENGL_LIBRARY} ${OPENAL_LIBRARY})
I also experienced unnecessary rebuilds using cmake and visual studio. The problem is related to an inappropriate x64 configuration parameter: Visual Studio 2008 Unnecessary Project Building
A simple solution in many of these cases is to completely wipe the build tree and regenerate it (and I mean something along the lines of rm -rf build && mkdir build && cd build && cmake -G "Unix Makefiles" ../src, not just make clean)