CMake Warning: Manually-specified variables were not used by the project: CMAKE_EXPORT_NO_PACKAGE_REGISTRY CMAKE_INSTALL_DATAROOTDIR CMAKE_INSTALL_LIBEXECDIR CMAKE_INSTALL_OLDINCLUDEDIR CMAKE_INSTALL_SBINDIR In file included from /home/conan/w/cci_PR-4017/.conan/data/mailio/0.20.0/_/_/build/1c66638edd75a2f398a175c44cdceb85bae3fd1d/source_subfolder/src/bit7.cpp:16: In file included from /home/conan/w/cci_PR-4017/.conan/data/boost/1.75.0/_/_/package/9dc4b589869441a4563a6e09d6b163e020952208/include/boost/algorithm/string/trim.hpp:23: In file included from /home/conan/w/cci_PR-4017/.conan/data/boost/1.75.0/_/_/package/9dc4b589869441a4563a6e09d6b163e020952208/include/boost/algorithm/string/classification.hpp:18: In file included from /home/conan/w/cci_PR-4017/.conan/data/boost/1.75.0/_/_/package/9dc4b589869441a4563a6e09d6b163e020952208/include/boost/algorithm/string/detail/classification.hpp:17: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/functional:60: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/unordered_map:47: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/bits/hashtable.h:37: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/bits/node_handle.h:39: /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:1032:27: error: use of class template 'optional' requires template arguments template optional(_Tp) -> optional<_Tp>; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:451:11: note: template is declared here class optional ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:1032:40: error: expected ';' at end of declaration template optional(_Tp) -> optional<_Tp>; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:1032:41: error: cannot use arrow operator on a type template optional(_Tp) -> optional<_Tp>; ^ 3 errors generated. make[2]: *** [source_subfolder/CMakeFiles/mailio.dir/src/bit7.cpp.o] Error 1 make[2]: *** Waiting for unfinished jobs.... In file included from /home/conan/w/cci_PR-4017/.conan/data/mailio/0.20.0/_/_/build/1c66638edd75a2f398a175c44cdceb85bae3fd1d/source_subfolder/src/base64.cpp:15: In file included from /home/conan/w/cci_PR-4017/.conan/data/boost/1.75.0/_/_/package/9dc4b589869441a4563a6e09d6b163e020952208/include/boost/algorithm/string/trim.hpp:23: In file included from /home/conan/w/cci_PR-4017/.conan/data/boost/1.75.0/_/_/package/9dc4b589869441a4563a6e09d6b163e020952208/include/boost/algorithm/string/classification.hpp:18: In file included from /home/conan/w/cci_PR-4017/.conan/data/boost/1.75.0/_/_/package/9dc4b589869441a4563a6e09d6b163e020952208/include/boost/algorithm/string/detail/classification.hpp:17: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/functional:60: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/unordered_map:47: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/bits/hashtable.h:37: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/bits/node_handle.h:39: /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:1032:27: error: use of class template 'optional' requires template arguments template optional(_Tp) -> optional<_Tp>; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:451:11: note: template is declared here class optional ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:1032:40: error: expected ';' at end of declaration template optional(_Tp) -> optional<_Tp>; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:1032:41: error: cannot use arrow operator on a type template optional(_Tp) -> optional<_Tp>; ^ 3 errors generated. make[2]: *** [source_subfolder/CMakeFiles/mailio.dir/src/base64.cpp.o] Error 1 In file included from /home/conan/w/cci_PR-4017/.conan/data/mailio/0.20.0/_/_/build/1c66638edd75a2f398a175c44cdceb85bae3fd1d/source_subfolder/src/bit8.cpp:16: In file included from /home/conan/w/cci_PR-4017/.conan/data/boost/1.75.0/_/_/package/9dc4b589869441a4563a6e09d6b163e020952208/include/boost/algorithm/string/trim.hpp:23: In file included from /home/conan/w/cci_PR-4017/.conan/data/boost/1.75.0/_/_/package/9dc4b589869441a4563a6e09d6b163e020952208/include/boost/algorithm/string/classification.hpp:18: In file included from /home/conan/w/cci_PR-4017/.conan/data/boost/1.75.0/_/_/package/9dc4b589869441a4563a6e09d6b163e020952208/include/boost/algorithm/string/detail/classification.hpp:17: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/functional:60: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/unordered_map:47: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/bits/hashtable.h:37: In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/bits/node_handle.h:39: /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:1032:27: error: use of class template 'optional' requires template arguments template optional(_Tp) -> optional<_Tp>; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:451:11: note: template is declared here class optional ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:1032:40: error: expected ';' at end of declaration template optional(_Tp) -> optional<_Tp>; ^ /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/optional:1032:41: error: cannot use arrow operator on a type template optional(_Tp) -> optional<_Tp>; ^ 3 errors generated. make[2]: *** [source_subfolder/CMakeFiles/mailio.dir/src/bit8.cpp.o] Error 1 make[1]: *** [source_subfolder/CMakeFiles/mailio.dir/all] Error 2 make: *** [all] Error 2 mailio/0.20.0: WARN: Build folder is dirty, removing it: /home/conan/w/cci_PR-4017/.conan/data/mailio/0.20.0/_/_/build/1c66638edd75a2f398a175c44cdceb85bae3fd1d mailio/0.20.0: ERROR: Package '1c66638edd75a2f398a175c44cdceb85bae3fd1d' build failed mailio/0.20.0: WARN: Build folder /home/conan/w/cci_PR-4017/.conan/data/mailio/0.20.0/_/_/build/1c66638edd75a2f398a175c44cdceb85bae3fd1d ERROR: mailio/0.20.0: Error in build() method, line 68 cmake.build() ConanException: Error 2 while executing cmake --build '/home/conan/w/cci_PR-4017/.conan/data/mailio/0.20.0/_/_/build/1c66638edd75a2f398a175c44cdceb85bae3fd1d/build_subfolder' '--' '-j3'