[CMake] User defined variable not propagating into subdirs

[Bill Hoffman]

Stephen Collyer wrote:
> I have a top-level cmake list file with this in it:
> 
> OPTION (MDP_BUILD_SHARED_LIBS "Build Shared Libraries" ON)
> SET (LIB_TYPE STATIC)
> IF (MDP_BUILD_SHARED_LIBS)
>   SET (LIB_TYPE SHARED)
>   IF (WIN32)
>     ADD_DEFINITIONS("-DMDP_BUILD_SHARED_LIBS")
>   ENDIF (WIN32)
> ENDIF (MDP_BUILD_SHARED_LIBS)
> 
> In a lower subdirectory, I have this to build a library:
> 
> ADD_LIBRARY(Test ${LIB_TYPE} Test.cpp)
> 
> the idea being that I can drive the generation of shared/static
> libraries via the setting of the MDP_BUILD_SHARED_LIBS setting
> which defaults to ON. However if I run cmake in an out-of-source
> build from scratch and run a "make all", it seems that LIB_TYPE
> is'nt being seen inside the lower subdirs - I've tested this by
> adding "SET (LIB_TYPE SHARED)" explicitly to the library cmake
> list file, then it build a shared library.
> 
> Can someone explain what's going on here. I'm beginning to
> tear my hair out.
> 
> And for added bonus: is there a cmake log file generated anywhere
> so I can see what it thinks it doing ? I can't find one anywhere.
> 
If you want to change all the libraries in your project to shared, you 
can use the global variable BUILD_SHARED_LIBS, and use add_library 
without specifying shared or static.

$ cmake --help-command add_library
cmake version 2.4-patch 7
   ADD_LIBRARY
        Add a library to the project using the specified source files.

          ADD_LIBRARY(libname [SHARED | STATIC | MODULE]
.....  If no keywords appear as the
        second argument, the type defaults to the current value of
        BUILD_SHARED_LIBS.  If this variable is not set, the type
        defaults to STATIC.



Log files are found in CMakeFiles directory.

-Bill