MantisBT - CMake
test cases:
PROJECT (${proj_name}) - OK
PROJECT (${proj_name}C CXX) - OK
without PROJECT command - OK
PROJECT (${proj_name}CXX) - FAIL
PROJECT (${proj_name}CXX C) - FAIL
CMAKE_SHARED_MODULE_CREATE_C_FLAGS gets its initial value in CMakeCInformation.cmake from CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS.
It seems that if CMakeCXXInformation.cmake is called before CMakeCInformation.cmake, The variable CMAKE_SHARED_MODULE_CREATE_CXX_FLAGS will take the default value of CMAKE_SHARED_MODULE_CREATE_C_FLAGS which is blank at that moment.
As shown in CMakeCXXInformation.cmake files:
161 # repeat for modules
162 IF(NOT CMAKE_SHARED_MODULE_CREATE_CXX_FLAGS)
163 SET(CMAKE_SHARED_MODULE_CREATE_CXX_FLAGS ${CMAKE_SHARED_MODULE_CREATE_C_FLAGS})
164 ENDIF(NOT CMAKE_SHARED_MODULE_CREATE_CXX_FLAGS)
The "-shared" gcc option is provided for SHARED library in any case.
Since CMakeGenericSystem.cmake gives CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS default value "-shared". And in CMakeCXXInformation.cmake, '-shared' is passed to CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS.
PROJECT (test CXX)
ADD_LIBRARY(a MODULE a.cpp)
a.cpp file:
int a(void){ return 0;
}
compile with MinGW, related log:
Linking CXX shared module liba.dll
C:\cmake-2.8.7-win32-x86\bin\cmake.exe -E cmake_link_script CMakeFiles\a.dir\link.txt --verbose=1
C:\cmake-2.8.7-win32-x86\bin\cmake.exe -E remove -f CMakeFiles\a.dir/objects.a
C:\MinGW\bin\ar.exe cr CMakeFiles\a.dir/objects.a @CMakeFiles\a.dir\objects1.rsp
C:\MinGW\bin\g++.exe -o liba.dll -Wl,--major-image-version,0,--minor-image-version,0 -Wl,--whole-archive CMakeFiles\a.dir/objects.a -Wl,--no-whole-archive -lkernel32 -luser32 -lgdi32 -lwinspool -lshell32 -lole32 -loleaut32 -luuid -lcomdlg32 -ladvapi32
c:/mingw/bin/../lib/gcc/mingw32/4.6.2/../../../libmingw32.a(main.o): In function `main':
C:\MinGW\msys\1.0\src\mingwrt/../mingw/main.c:73: undefined reference to `WinMain@16'
in which, CMAKE_SHARED_MODULE_CREATE_CXX_FLAGS is empty rather than '-shared' which cause the failure.
0001-WIP-Fix-CXX-Fortran-MODULE-flags-when-enabled-before.patch (3,217) 2012-02-03 10:45https://public.kitware.com/Bug/file/4203/0001-WIP-Fix-CXX-Fortran-MODULE-flags-when-enabled-before.patch