Rather than email one of the folks at Kitware, I decided to join the CMake mailing list... Hello all for those who remember me.
I apologize for the long email. A few of us have been trying to port GT.M (https://www.fisglobal.com/Solutions/Services/Database-Engine) to Cygwin, 1. to get it running on Windows 2. as an exercise to prepare for harder ports, the Raspberry Pi being the holy grail here. That's the background. The problem we are having is familiar to many; but not initially to me. See the heading "Shared libraries with Windows/MinGW" in this article: http://gernotklingler.com/blog/creating-using-shared-libraries-different-compilers-different-operating-systems/. CMakeLists.txt: https://github.com/shabiel/fis-gtm/blob/cygwin/CMakeLists.txt The error: [ 88%] Linking C shared module plugin/cyggtmcrypt_gcrypt_AES256CFB.dll CMakeFiles/libgtmcrypt_gcrypt_AES256CFB.so.dir/sr_unix/gtmcrypt_util.c.o: In function `gc_load_gtmshr_symbols': /home/sam/fis-gtm-cygwin/sr_unix/gtmcrypt_util.c:100: undefined reference to `gtm_malloc' /home/sam/fis-gtm-cygwin/sr_unix/gtmcrypt_util.c:101: undefined reference to `gtm_free' collect2: error: ld returned 1 exit status CMakeFiles/libgtmcrypt_gcrypt_AES256CFB.so.dir/build.make:202: recipe for target 'plugin/cyggtmcrypt_gcrypt_AES256CFB.dll' failed make[2]: *** [plugin/cyggtmcrypt_gcrypt_AES256CFB.dll] Error 1 CMakeFiles/Makefile2:891: recipe for target 'CMakeFiles/libgtmcrypt_gcrypt_AES256CFB.so.dir/all' failed make[1]: *** [CMakeFiles/libgtmcrypt_gcrypt_AES256CFB.so.dir/all] Error 2 Makefile:116: recipe for target 'all' failed make: *** [all] Error 2 Here's the link command (I turned CMAKE_VERBOSE_MAKEFILE=ON): /usr/bin/cc -march=i586 -fsigned-char -Wmissing-prototypes -Wreturn-type -Wpointer-sign -fno-omit-frame-pointer -g -DDEBUG -shared -Wl,--enable-auto-import -o plugin/cyggtmcrypt_gcrypt_AES256CFB.dll -Wl,--major-image-version,0,--minor-image-version,0 CMakeFiles/libgtmcrypt_gcrypt_AES256CFB.so.dir/sr_unix/gtmcrypt_ref.c.o CMakeFiles/libgtmcrypt_gcrypt_AES256CFB.so.dir/sr_unix/gtmcrypt_pk_ref.c.o CMakeFiles/libgtmcrypt_gcrypt_AES256CFB.so.dir/sr_unix/gtmcrypt_dbk_ref.c.o CMakeFiles/libgtmcrypt_gcrypt_AES256CFB.so.dir/sr_unix/gtmcrypt_sym_ref.c.o CMakeFiles/libgtmcrypt_gcrypt_AES256CFB.so.dir/sr_unix/gtmcrypt_util.c.o -lgpg-error -lgpgme -lgcrypt /usr/local/lib/libconfig.dll.a What is missing is that there needs to be either a link to cyggtmshr.dll, or a way for CMake to know to generate a libgtmshr_import.lib and add it to the link command. So here is what I tried: 1. Using the GenerateExportHeader functionality of CMake on libgtmshr. If I do that, it doesn't seem to generate the import library; but it sure does generate an export header, which I don't need. Here it is: include(GenerateExportHeader) generate_export_header(libgtmshr BASE_NAME libgtmshr EXPORT_MACRO_NAME libgtmshr_EXPORTS EXPORT_FILE_NAME libgtmshr_EXPORTS.h STATIC_DEFINE SHARED_EXPORTS_BUILT_AS_STATIC) 2. Explicitly adding a libgtmshr as a dependency on line https://github.com/shabiel/fis-gtm/blob/cygwin/CMakeLists.txt#L531, but only for Cygwin. I get this error message: CMake Error at CMakeLists.txt:542 (target_link_libraries): Target "libgtmshr" of type MODULE_LIBRARY may not be linked into another target. One may link only to STATIC or SHARED libraries, or to executables with the ENABLE_EXPORTS property set. The GT.M developer familiar with CMake suggested me to use LINK_FLAGS and have CMake use the file by us hardcoding it in; which I am okay doing, but I thought I would check to see if there is an alternative way of doing this. I also tried the suggestions here: "https://blog.kitware.com/create-dlls-on-windows-without-declspec-using-new-cmake-export-all-feature/"; to no avail. Last, but not least: sam@horus ~/fis-gtm-cygwin $ cmake --version cmake version 3.4.3 CMake suite maintained and supported by Kitware (kitware.com/cmake). sam@horus ~/fis-gtm-cygwin $ uname -a CYGWIN_NT-10.0-WOW horus 2.2.0(0.289/5/3) 2015-08-03 12:49 i686 Cygwin -- Sam Habiel, Pharm.D. VISTA Expertise Network -- 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
