[CMake] simple project in Visual Studio 2008

[Hendrik Sattler]

Zitat von Mike Jackson <mike.jackson at imts.us>:
> BUILD_SHARED_LIBS: Global flag to cause add_library to create shared
> libraries if on.
>
> If present and true, this will cause all libraries to be built shared
> unless the library was explicitly added as a static library. This
> variable is often added to projects as an OPTION so that each user of a
> project can decide if they want to build the project using shared or
> static libraries.
>
> Most projects do in-fact add this as an option so that the libraries
> can be built as Static or Dynamic so I added it here. I will make a
> note in the Wiki.

They add this so that it is directly visible in e.g. ccmake. Saves  
some manual typing. Nothing else implied.

>> 2.
>> "#if defined(_MSC_VER)" is working for MSVC but gcc can also do   
>> __declspec(dllexport) on Win32 and other Windows compilers probably  
>>  too.
>> You can use "#if defined(_WIN32)" for gcc and msvc.
>>
>> The result (and that's _all_ that is needed, works with cmake and libtool):
>> #if defined(_WIN32)
>> #  if defined(MyLibrary_EXPORTS) or defined(DLL_EXPORT)

s/or/||/

> I am going to leave out the GCC until I can get a
> concise example based on the GCC web page working. I do not use that
> GCC Feature in my projects (yet) so I probably would mess up any
> example that I tried to write at the moment.

I used it in various projects except the default visibility classes  
with hidden members. Just one hint: member functions available via  
virtual function tables do not need to be exported as they are always  
accessed via the VFT.
Additionally, you should always allocate and destroy a class in the  
same library or executable, just in case you link to different runtime  
implementations (e.g. from different MSVC versions). And that is  
common on Windows.

HS