On Jun 26, 2011, at 7:12 AM, Owen Shepherd wrote: > On 25/06/2011 07:30, "Michael Hertling" <mhertl...@online.de> wrote: > >> On 06/24/2011 04:16 PM, Owen Shepherd wrote: >>> I think the appropriate solution here is a project-specific dialect >>> flag - >>> perhaps one taking options in the GNU format since it seems most >>> familiar. >>> One could perhaps generalise this further - a file-specific dialect flag >>> which defaults to the value of the project-specific flag >> >> If there are individual compilers for C89/C99, and a projects needs a >> C99 one, any dialect flags - project/directory/target/file specific - >> would be of no use, wouldn't they? Rather, one must specify the C99 >> compiler if it isn't found automatically by CMake during the initial >> configuration, and the project might consider to check the compiler's >> C99 capabilities. > > Sorry - I should have said property rather than flag. That is, something > along the lines of > set_target_properties(the_target PROPERTIES C_DIALECT C99) > Or > set_source_files_properties(myfile.c PROPERTIES C_DIALECT C99) > > (I'm not entirely sure here whether the source file property should be > C_DIALECT or just DIALECT. The language, after all, should be unambiguous > at this point) > > It would then be the responsibility of the Cmake machinery to choose the > right compiler and set it up for building code with the given dialect.
I *think* Michael's concern here is that if you have a project that uses C99, it should fail as fast as possible, e.g. when it knows that the detected/provided compiler does not support C99 as it processes the 'project' command at the beginning of the CMakeLists.txt file. I think it would be acceptable if things failed later than that. e.g., you could have: > project(foo C CXX) Suppose a C89-only compiler is detected. The build now knows that's the only dialect it supports. It should fail when it sees this later: > set_target_properties(the_target PROPERTIES C_DIALECT C99) If, however, there is a C99 file that does NOT have such a property set on it, I don't think there is anything you can do about that. Here, the build would just fail when it tries to compile that file. I think the right behavior is to keep the current behavior for files/targets/projects that do not have dialect properties set on them. -Todd > > -- Owen Shepherd > http://www.owenshepherd.net > owen.sheph...@e43.eu (general) / oshephe...@shef.ac.uk (academic) > > > > > _______________________________________________ > Powered by www.kitware.com > > Visit other Kitware open-source projects at > http://www.kitware.com/opensource/opensource.html > > Please keep messages on-topic and check the CMake FAQ at: > http://www.cmake.org/Wiki/CMake_FAQ > > Follow this link to subscribe/unsubscribe: > http://www.cmake.org/mailman/listinfo/cmake ______________________________________________________________________ Todd Gamblin, tgamb...@llnl.gov, http://people.llnl.gov/gamblin2 CASC @ Lawrence Livermore National Laboratory, Livermore, CA, USA _______________________________________________ Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
