I Try to build an application using Qwt with CMake on a MacOS virtual machine.
I installed Qt5 and Qwt using brew:
brew install qt5 qwt
The result is a Qwt framework installation.
The header is there:
/usr/local/Cellar/qwt/6.1.4/lib/qwt.framework/Versions/6/Headers/qwt.h
and the library is here
file /usr/local/Cellar/qwt/6.1.4/lib/qwt.framework/qwt
/usr/local/Cellar/qwt/6.1.4/lib/qwt.framework/qwt: Mach-O 64-bit dynamically linked shared library x86_64
It is easy to use it during buid with qmake
LIBS+= -F/usr/local/Cellar/qwt/6.1.4/lib
LIBS += -framework qwt
but I'm stuck with CMake.I don't succeed to find how to do the same.
I have written my own FindQwt module based on find_library has indicated in CMake documentation. It works very well on Linux but I don't succeed to make it works on MacOS without the following hacks:
symbolic links to make appear qwt headers in an include directory and qwt as libqwt.dyn_lib:
ln -sf /usr/local/Cellar/qwt/6.1.4/lib/qwt.framework/Versions/6/Headers /usr/local/Cellar/qwt/6.1.4/include
ln -sf /usr/local/Cellar/qwt/6.1.4/lib/qwt.framework/qwt /usr/local/Cellar/qwt/6.1.4/libqwt.dylib
I also have to remove /usr/local/lib/qwt.framework ( symbolic link on /usr/local/Cellar/qwt/6.1.4/lib/qwt.framework ) that was found by my FindQwt Cmake module after the 2 previous hack but I don't find any reason for that and was causing a link issue ( ld error 22 )
Here is the code of my Qwt cmake module
find_package(PkgConfig)
pkg_check_modules(PC_QWT QUIET libqwt)
if("${PC_QWT}" STREQUAL "")
set(QWT_HINTS $ENV{QWT_INSTALL})
set(QWT_PATHS
/usr
/usr/local/
/usr/local/share/
/usr/share/
)
if(NOT ${QWT_HINTS} STREQUAL "")
set(QWT_PATHS ${QWT_HINTS})
endif(NOT ${QWT_HINTS} STREQUAL "")
find_path(Qwt_INCLUDE_DIR
NAMES qwt.h
PATHS ${QWT_PATHS}
HINTS ${QWT_HINTS}
PATH_SUFFIXES include qwt-qt4 qwt-qt5 qwt
DOC "Variable storing the location of Qwt header"
)
set(ARCH_SUFFIX "lib")
if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
set(ARCH_SUFFIX "")
endif("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
find_library(Qwt_LIBRARY
NAMES qwt qwt-qt4 qwt-qt5
PATHS ${QWT_PATHS}
HINTS ${QWT_HINTS}
PATH_SUFFIXES ${ARCH_SUFFIX}
DOC "Variable storing the location of Qwt library"
NO_DEFAULT_PATH
NO_CMAKE_PATH
)
set(Qwt_VERSION ${Qwt_FIND_VERSION})
include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(Qwt
FOUND_VAR Qwt_FOUND
REQUIRED_VARS
Qwt_LIBRARY
Qwt_INCLUDE_DIR
VERSION_VAR Qwt_VERSION
)
if(Qwt_FOUND)
set(Qwt_LIBRARIES ${Qwt_LIBRARY})
set(Qwt_INCLUDE_DIRS ${Qwt_INCLUDE_DIR})
#set(Qwt_DEFINITIONS ${PC_Qwt_CFLAGS_OTHER})
endif()
if(Qwt_FOUND AND NOT TARGET Qwt::Qwt)
add_library(Qwt::Qwt UNKNOWN IMPORTED)
set_target_properties(Qwt::Qwt PROPERTIES
IMPORTED_LOCATION "${Qwt_LIBRARY}"
INTERFACE_COMPILE_OPTIONS ""
INTERFACE_INCLUDE_DIRECTORIES "${Qwt_INCLUDE_DIR}")
endif()
endif("${PC_QWT}" STREQUAL "")
If you have some ideas some ideas to avoid the hacks described above and hanle it in a more elegant way with CMake module they will be welcomed
Solution working without previously described hacks
Here is the code
find_package(PkgConfig)
pkg_check_modules(PC_QWT QUIET libqwt)
if("${PC_QWT}" STREQUAL "")
set(QWT_HINTS $ENV{QWT_INSTALL})
set(QWT_PATHS
/usr
/usr/local/
/usr/local/share/
/usr/share/
)
if(NOT ${QWT_HINTS} STREQUAL "")
set(QWT_PATHS ${QWT_HINTS})
endif(NOT ${QWT_HINTS} STREQUAL "")
find_path(Qwt_INCLUDE_DIR
NAMES qwt.h
PATHS ${QWT_PATHS}
HINTS ${QWT_HINTS}
PATH_SUFFIXES include qwt-qt4 qwt-qt5 qwt Headers
DOC "Variable storing the location of Qwt header"
)
set(ARCH_SUFFIX "lib")
if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
set(ARCH_SUFFIX "")
endif("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
find_library(Qwt_LIBRARY
NAMES qwt qwt-qt4 qwt-qt5
PATHS ${QWT_PATHS}
HINTS ${QWT_HINTS}
PATH_SUFFIXES ${ARCH_SUFFIX}
DOC "Variable storing the location of Qwt library"
)
set(Qwt_VERSION ${Qwt_FIND_VERSION})
include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(Qwt
FOUND_VAR Qwt_FOUND
REQUIRED_VARS
Qwt_LIBRARY
Qwt_INCLUDE_DIR
VERSION_VAR Qwt_VERSION
)
if(Qwt_FOUND)
set(Qwt_LIBRARIES ${Qwt_LIBRARY})
set(Qwt_INCLUDE_DIRS ${Qwt_INCLUDE_DIR})
endif()
if(Qwt_FOUND AND NOT TARGET Qwt::Qwt)
if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
get_filename_component(FRAMEWORK_LOC ${Qwt_LIBRARY} DIRECTORY)
add_library(Qwt::Qwt INTERFACE IMPORTED)
set_target_properties(Qwt::Qwt PROPERTIES
INTERFACE_COMPILE_OPTIONS ""
INTERFACE_INCLUDE_DIRECTORIES "${Qwt_INCLUDE_DIR}"
)
target_link_libraries(Qwt::Qwt INTERFACE "-F${FRAMEWORK_LOC} -framework qwt")
else("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
add_library(Qwt::Qwt UNKNOWN IMPORTED)
set_target_properties(Qwt::Qwt PROPERTIES
IMPORTED_LOCATION "${Qwt_LIBRARIES}"
INTERFACE_COMPILE_OPTIONS ""
INTERFACE_INCLUDE_DIRECTORIES "${Qwt_INCLUDE_DIR}"
)
endif("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
endif()
endif("${PC_QWT}" STREQUAL "")
Assuming that you are already familiar with cmake/qt basics, this is my proposal:
if(APPLE)
set(CMAKE_FIND_FRAMEWORK ONLY)
find_library(QWT
NAMES qwt
HINTS /usr/local/opt/qwt/lib/
REQUIRED)
if(QWT)
include_directories(${QWT}/Headers)
link_libraries(${QWT})
message("QWT found: ${QWT}")
endif()
endif()
The CMake variable CMAKE_FIND_FRAMEWORK affects how find_* commands choose between macOS Frameworks and unix-style dylibs. You may observe that executing cmake with the above snippet outputs:
QWT found: /usr/local/Cellar/qwt/6.1.4/lib/qwt.framework
This snippet adds the qwt framework to any target defined in your CMakeLists.txt, but you may prefer to apply the link part to only one target, like this:
target_link_libraries(yourtarget ${QWT})
Another caveat: you should link your program to the same Qt5 frameworks linked by Qwt, and also installed by brew: QTDIR=/usr/local/opt/qt5