[CMake] Darwin, shared libraries, and undefined symbols

[Brad King]

Zachary Pincus wrote:
> Some time ago (~CMake 1.6 or 1.8?), the Modules/Platform/Darwin.cmake 
> file defined
>     CMAKE_SHARED_MODULE_CREATE_C_FLAGS
> to contain
>     -bundle -flat_namespace -undefined suppress
[snip]
> So: what is the preferred way to deal with undefined symbols? 
> Darwin-specific stuff in a CMakeLists file? (And if so, hat stuff? 
> specifying a bundle_loader? Setting some -undefined handler?) Or is 
> there a better cross-platform way to deal with making such libraries? 
> Clearly there is some way because SWIG-wrapped python libs get made 
> properly in Darwin...

CMake will pay attention to the last setting of this variable it sees in 
a directory.  The modules directory code just initializes it.  You can 
write code to set the variable to whatever you want:

IF(APPLE)
   SET(CMAKE_SHARED_MODULE_CREATE_C_FLAGS
       "${CMAKE_SHARED_MODULE_CREATE_C_FLAGS} -flat_namespace -undefined 
suppress")
ENDIF(APPLE)

The preferred way to deal with undefined symbols is to not have any 
because DLLs on windows must be fully resolved at link time.

-Brad