Jakob, I don't think there is any confusion about what REQUIRED means. Whether or not REQUIRED is provided, the list of OPTIONAL_COMPONENTS should not be required under any circumstances. The example error message seems pretty clear to me that the expected behavior and actual behavior are different. I went and looked at the source code of the find module:
https://github.com/Kitware/CMake/blob/master/Modules/FindQt4.cmake It seems that there is no check whatsoever for Qt4_FIND_REQUIRED_<component>, so the find module just blindly assumes that all components are required. More info: https://cmake.org/cmake/help/latest/manual/cmake-developer.7.html#find-modules To me this seems like a bug in the find module. On Tue, Mar 8, 2016 at 9:34 AM, Jakob van Bethlehem <jsvanbethle...@gmail.com> wrote: > Hej Alexander, > > Yes, you're missing a subtle detail. You assume that the 'REQUIRED' keyword > reflects the fact that COMPONENTS are required. This is not the case. The > REQUIRED keyword reflects that the entire package Qt4 is required, see > https://cmake.org/cmake/help/v3.0/command/find_package.html where it says: > 'The REQUIRED option stops processing with an error message if the package > cannot be found' > > Confusing, I agree. > > Sincerely, > Jakob > > On Fri, Mar 4, 2016 at 9:18 AM, Alexander Stein > <alexander.stein+cm...@mailbox.org> wrote: >> >> Hi, >> >> I want to use some required Qt component while others are optional. >> Apparently if you specify REQUIRED in find_package OPTIONAL_COMPONENTS is >> ignored. >> Here is a minimal CMakeLists.txt: >> project(test) >> cmake_minimum_required(VERSION 3.5) >> >> find_package(Qt4 REQUIRED COMPONENTS QtCore QtGui OPTIONAL_COMPONENTS >> Invalid) >> >> /home/alex/repo/cmake/build/bin/cmake --version >> cmake version 3.5.20160303-gf37f >> >> cmake fails with: >> CMake Error at >> /home/alex/repo/cmake/Modules/FindPackageHandleStandardArgs.cmake:148 >> (message): >> Could NOT find Qt4 (missing: QT_INVALID_INCLUDE_DIR QT_INVALID_LIBRARY) >> (found version "4.8.7") >> Call Stack (most recent call first): >> /home/alex/repo/cmake/Modules/FindPackageHandleStandardArgs.cmake:388 >> (_FPHSA_FAILURE_MESSAGE) >> /home/alex/repo/cmake/Modules/FindQt4.cmake:1333 >> (FIND_PACKAGE_HANDLE_STANDARD_ARGS) >> CMakeLists.txt:4 (find_package) >> >> I expected that if required components are missing cmake bails out while >> continuing when OPTIONAL_COMPONENTS are missing. My current workaround is: >> find_package(Qt4 OPTIONAL_COMPONENTS Invalid) >> find_package(Qt4 REQUIRED COMPONENTS QtCore QtGui) >> >> But I would rather use a single line. Am I missing something here? >> >> Best regards, >> Alexander >> >> -- >> >> Powered by www.kitware.com >> >> Please keep messages on-topic and check the CMake FAQ at: >> http://www.cmake.org/Wiki/CMake_FAQ >> >> Kitware offers various services to support the CMake community. For more >> information on each offering, please visit: >> >> CMake Support: http://cmake.org/cmake/help/support.html >> CMake Consulting: http://cmake.org/cmake/help/consulting.html >> CMake Training Courses: http://cmake.org/cmake/help/training.html >> >> Visit other Kitware open-source projects at >> http://www.kitware.com/opensource/opensource.html >> >> Follow this link to subscribe/unsubscribe: >> http://public.kitware.com/mailman/listinfo/cmake > > > > -- > > Powered by www.kitware.com > > Please keep messages on-topic and check the CMake FAQ at: > http://www.cmake.org/Wiki/CMake_FAQ > > Kitware offers various services to support the CMake community. For more > information on each offering, please visit: > > CMake Support: http://cmake.org/cmake/help/support.html > CMake Consulting: http://cmake.org/cmake/help/consulting.html > CMake Training Courses: http://cmake.org/cmake/help/training.html > > Visit other Kitware open-source projects at > http://www.kitware.com/opensource/opensource.html > > Follow this link to subscribe/unsubscribe: > http://public.kitware.com/mailman/listinfo/cmake -- Powered by www.kitware.com Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: http://public.kitware.com/mailman/listinfo/cmake
