On 05/10/2011 12:19 PM, Erlend Pedersen wrote: > I am having problems with Fortran linking that doesn't work when > building static libraries, only when building shared libraries. I am > using cmake from Ubuntu 10.04 (2.8.0-5ubuntu1). > > I use CMake to build a project, including project-internal shared > libraries. All executables are Fortran, but one of the internal > libraries contain minimal sprinklings of C and C++. All works well when > building shared libraries, but when I switch to building static > libraries, CMake decides to try to link all Fortran executables as if > they were C++. Unfortunately, this means that the main function is not > properly located, and linking fails. > > I tried forcing Fortran linkage on libraries only (hoping this would > propagate into the executables that link to them), using > > SET_TARGET_PROPERTIES(<libname> PROPERTIES LINKER_LANGUAGE Fortran) > > and when building the libraries, output shows that they are indeed > treated as Fortran static libraries. But the executables (typically > conisting of a single .f90 file, and linked to one or more of the > internal libraries) are still treated as C++. > > Only when I force the LINKER_LANGUAGE by using SET_TARGET_PROPERTIES on > both libraries and executables does things build properly. But that > seems needlessly redundant and noisy and redundant. > > Is there some easier way I can convince CMake to link the executables > correctly? Is this a bug?
No, this isn't a bug. The behaviour you observe occurs because of CMAKE_CXX_LINKER_PREFERENCE_PROPAGATES==TRUE CMAKE_CXX_LINKER_PREFERENCE==30 > 20==CMAKE_Fortran_LINKER_PREFERENCE i.e. when a static library with C++ code is mixed with Fortran code, the C++ linker is taken into account along with the Fortran linker, and C++ will win; this does not apply to _shared_ libraries. Hence, setting CMAKE_CXX_LINKER_PREFERENCE_PROPAGATES to FALSE is probably the appropriate solution in your case, i.e. Fortran code with one, say, C++-contaminated _static_ library. Alternatively, you might raise the Fortran linker preference above the C++ linker's one. 'hope that helps. Regards, Michael _______________________________________________ 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
