On Wed, Jul 15, 2009 at 2:18 AM, Hendrik Sattler<p...@hendrik-sattler.de> wrote: > Zitat von Benjamin Schindler <bschind...@inf.ethz.ch>: >> >> I'm working on a project which builds both on linux and windows. I >> generated an eclipse project out of it which works basically fine but >> it's not able to recognize i.e. the __GNUC__ macro (and probably any >> other macro defined per default on gcc) are not recognized by eclipse. >> That means that by using a header like: >> >> #if defined(_MSC_VER) && (_MSC_VER >= 1300) >> #ifdef FLOW_DLL_EXPORT >> #define FLOW_DLL _declspec(dllexport) >> #else >> #define FLOW_DLL _declspec(dllimport) >> #endif >> #else >> #ifdef __GNUC__ >> #define FLOW_DLL >> #endif >> #endif > > I know that it's unrelated to your question but this code is slightly wrong. > For the windows version of gcc, it also understands the _declspec() thing. > You don't make it compiler-specific but system-specific. > Additionally, on non-windows systems, you can use the visibility attribute > to achieve something similar. > That's why the gcc people suggest the following at > http://gcc.gnu.org/wiki/Visibility (I simplified it): > #if defined _WIN32 || defined __CYGWIN__ > #ifdef FLOW_DLL_EXPORT > #define FLOW_DLL __declspec(dllexport) > #else > #define FLOW_DLL __declspec(dllimport) > #endif > #elif __GNUC__ >= 4 > #define FLOW_DLL __attribute__ ((visibility("default"))) > #define DLL_LOCAL __attribute__ ((visibility("hidden"))) > #endif > #ifndef FLOW_DLL > #define FLOW_DLL > #endif > #ifndef DLL_LOCAL > #define DLL_LOCAL > #endif > > You only need to add -fvisibility=hidden to gcc command line on non-windows > systems. > The above still has the flaw you use _declspec(dllimport) when compiling the > library as static library. That's ok if you don't intend to do so else easy > to fix. > > Additionally, eclipse may not select the right choice but the macros will > not error out as they are _always_ defined in some way. > > Have fun > > HS
I think I need some explanation on this logic. This line: #if defined _WIN32 || defined __CYGWIN__ will always be true on msvc, mingw and cygwin because _WIN32 is defined for the MS compilers and when MinGW is being used so the "#elif" will _never_ get executed? Where am I going wrong on this? I put the following at the top of a source file and compiled with MinGW and got an error: #ifdef _WIN32 #error Um what is wrong #endif I looked at the GCC page cited above and I think it would have the same problem. Mike -- Mike Jackson mike.jack...@bluequartz.net BlueQuartz Software www.bluequartz.net _______________________________________________ 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
