Difference between revisions of "CMake/Examples"
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<source lang="cmake"> | <source lang="cmake"> | ||
MESSAGE("Hello world") | MESSAGE("Hello world") | ||
</source> | |||
===Output a Variable=== | |||
<source lang="cmake"> | |||
message("VTK Using Boost? ${VTK_USE_BOOST}") | |||
</source> | </source> | ||
Revision as of 16:03, 2 August 2011
Welcome to the CMake Wiki Examples! These short snippets which show you how to perform many common CMake procedures. Please see [1] for the verbose documentation.
Please add examples as you find common procedures which are not explained here!
Basics
Set a CMake variable
SET(VARIABLE VALUE)
View a CMake variable
MESSAGE("CMAKE_BINARY_DIR: ${CMAKE_BINARY_DIR}")
View a system variable
MESSAGE("$ENV{PATH}")
Check operating system
IF(WIN32)
...do something...
ELSE(WIN32)
...do something else...
ENDIF(WIN32)
Check operating system
IF(CMAKE_SYSTEM_NAME STREQUAL Linux)
Outputs
Message
MESSAGE("Hello world")
Output a Variable
message("VTK Using Boost? ${VTK_USE_BOOST}")
Error
MESSAGE(FATAL_ERROR "An error occured.")
Conditional Statement (if)
There are two allowable syntaxes:
if(something)
do something
else(something) # the argument must match the if(...)
do something else
endif(something) # the argument must match the if(...)
The following is also allowed. It is easier to read (because "else(the same thing)" doesn't really make sense if you read it like c++, for example), but it is also easier to confuse yourself with nested ifs.
if(something)
do something
else()
do something else
endif()
Example:
if (!VTK_USE_BOOST)
MESSAGE(SEND_ERROR "VTK must be built with VTK_USE_BOOST=ON.")
endif ()
Logical Operators
These operators work exactly as you would expect.
AND
if(A AND B)
OR
if(A OR B)
NOT
if(NOT A)
Compound
if(NOT(A AND B))
Finding Packages
Most of the time large packages will have their Find[PackageName].cmake file included in the cmake distribution. If that is the case, all you must do it:
FIND_PACKAGE(Eigen3)
Specifying where to look for .cmake files
If you place your FindXYZ.cmake and UseXYZ.cmake files in the same directory as your main CMakeLists.txt file, you can tell CMake to try to use them first before looking at system paths by doing:
set(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/" ${CMAKE_MODULE_PATH})
Checking if a package was found
Most of the time the [PackageName]_FOUND variable is defined. You can use it like this:
FIND_PACKAGE(Eigen3)
if(EIGEN3_FOUND)
... do something ...
endif(EIGEN3_FOUND)
Suppress warnings
Sometimes you may want to optionally include a package. You can suppress the warning about the package not being found with:
FIND_PACKAGE(Eigen3 QUIET)
Fix Mininum Version Error/Warning
cmake_minimum_required(VERSION 2.6.0 FATAL_ERROR)
Look in the directory that the CMakeLists.txt file is for header and implementation files
INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR})
or
INCLUDE_DIRECTORIES(${CMAKE_CURRENT_SOURCE_DIR})
Set Link Directories
If a library you are using does not have a [LibraryName].cmake, you can do
find_library(OPENSSL_LIB ssl $ENV{OPENSSL_LIB_PATH})
This will check the environment for a variable named OPENSSL_LIB_PATH. If it exists, you can then use
target_link_libraries(mytarget ${OPENSSL_LIB})
If it does not, it can be set through the CMake GUI.
Set Include Directories
This command adds a path to the include directories, you do NOT have to do the 'export' style ``keep everything that is here and add this one syntax.
INCLUDE_DIRECTORIES(/some/directory)
View the directories that are set
get_property(inc_dirs DIRECTORY PROPERTY INCLUDE_DIRECTORIES)
message("inc_dirs = ${inc_dirs}")
Automate configure and generate
Note 'cmake' instead of 'ccmake' (ccmake is curses cmake (curses is the terminal gui))
cmake -DCMAKE_BUILD_TYPE=Debug -DCMAKE_INSTALL_PREFIX=/usr/mylocation ../
Compiler options
Set a cmake flag
ccmake ../../src/boost -DCMAKE_IS_EXPERIMENTAL=YES_I_KNOW
Set a cpp flag/preprocessor definition
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D__WXGTK__")
Force g++
Ocassionally you will come across files with the extension .c that actually contain c++ code. CMake treats the file based on its extension. If you want to override this behavior (in this case, compile .c files with your c++ compiler), do the following:
set(MySources main.c anotherFile.c)
add_executable(SpinRecognize ${MySource})
set_source_files_properties(${MySources} PROPERTIES LANGUAGE CXX)
Per-target
set_target_properties(myexe_target
PROPERTIES COMPILE_FLAGS "-Wall")
Set the default build type
SET(CMAKE_BUILD_TYPE Debug CACHE STRING "default to debug" FORCE)
Custom variable
Here is a list of supported variable types: http://www.cmake.org/cmake/help/cmake2.6docs.html#command:set
String
SET(BUILD_PARAVIEW_PLUGIN ON CACHE STRING "Build Paraview plugin?" FORCE)
Bool
SET(DAI_WITH_BP ON CACHE BOOL "Belief Propagation" FORCE)
Comparison
if(DAI_WITH_BP EQUALS ON)
#do something
endif(DAI_WITH_BP EQUALS ON)
This is equivalent to
if(DAI_WITH_BP)
#do something
endif(DAI_WITH_BP)
Linking to specific libraries
ITK
Add the path to your environment:
export ITK_DIR=/home/doriad/bin/ITK
Then in the CMakeLists.txt use:
FIND_PACKAGE(ITK REQUIRED)
INCLUDE(${ITK_USE_FILE})
ADD_EXECUTABLE(CastImageFilter CastImageFilter.cxx)
TARGET_LINK_LIBRARIES(CastImageFilter
vtkHybrid
ITKIO ITKBasicFilters ITKCommon
)
VXL
Add the path to your environment:
export VXLBIN="/home/doriad/bin/vxl"
Then in the CMakeLists.txt use:
FIND_PACKAGE(VXL REQUIRED)
INCLUDE(${VXL_CMAKE_DIR}/UseVXL.cmake)
VTK
Add the path to your environment:
export VTK_DIR="/home/doriad/bin/VTK"
Then in the CMakeLists.txt use:
FIND_PACKAGE(VTK REQUIRED)
INCLUDE(${VTK_USE_FILE})
Boost
Lets assume we built boost with ./bjam --prefix=/home/doriad/bin install
Then for CMake to find Boost, all you need is to add to your .bashrc:
export BOOST_ROOT="/home/doriad/bin"
Then in the CMakeLists.txt use:
SET(Boost_USE_MULTITHREAD ON) #set a flag
FIND_PACKAGE(Boost)
INCLUDE_DIRECTORIES(${INCLUDE_DIRECTORIES} ${Boost_INCLUDE_DIRS})
LINK_DIRECTORIES(${LINK_DIRECTORIES} ${Boost_LIBRARY_DIRS})
OpenCV
Add to the environment:
export OpenCV_DIR=/home/doriad/bin/OpenCV
Then in the CMakeLists.txt use:
FIND_PACKAGE(OpenCV REQUIRED )
INCLUDE_DIRECTORIES( ${OPENCV_INCLUDE_DIR} )
ADD_EXECUTABLE(Scalar Scalar.cxx)
TARGET_LINK_LIBRARIES(Scalar ${OpenCV_LIBS})
Get Help Using a Library
cmake --help-module FindBoost
Add new libraries to CMake
/usr/share/cmake/Modules/FindOpenGL.cmake|
Dependency Graph
ccmake ../src/Program/ --graphviz=test.graph
dotty test.graph
CTest
Run a specific test by number
e.g. Test 622
ctest -I 622,622
Run a range of tests
e.g. Test 622 to 625
ctest -I 622,625
Run a test by name
ctest -R "itkTransformPoint*"|
Show verbose output of a test
ctest -V -R "itkTransformPoint*"|
Create a Test
cmake_minimum_required(VERSION 2.6)
project(simple)
ENABLE_TESTING()
add_executable(simple simple.cpp)
add_test(SimpleTest simple)
Link to a library
ADD_EXECUTABLE(ColoredLines ColoredLines.cpp)
TARGET_LINK_LIBRARIES(ColoredLines vtkHybrid)
Create a library
add_library(MatlabLibrary ./MatlabDll/LidarK.cpp)
Installing executables
Once your project is built, you can use the 'install' make target to copy the executables to the directory specified by CMAKE_INSTALL_PREFIX.
add_executable(test test.cxx)
install(TARGETS test RUNTIME DESTINATION ${CMAKE_INSTALL_PREFIX})
If you get an error like:
error while loading shared libraries: I get libwx_gtk2u_core-2.9.so.1: cannot open shared object file: No such file or directory
you should add:
SET(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
to your CMakeLists.txt file.