[CMake] Eclipse generator - basic macros

[Benjamin Schindler]

Hei, thanks for the thorough review and hints. I'll surely apply them

Thanks
Benjamin

Hendrik Sattler wrote:
> Zitat von Benjamin Schindler <bschindler at 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
>
>
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