[CMake] Making a Top Level CMakeLists File and Dependant libraries

[Brad King]

Mike Jackson wrote:
> I am trying to create a Top level Cmakelists.txt file to build my
> project. My project is laid out kinda like vtk in that we have
> subfolders with base libraries to be built in a specific order.
> 
> I have the first few lines in this top level cmake file to be:
> 
> 
> SUBDIRS (
> Fox/Core
> Fox/Views
> Fox
> )
> 
> So I run cmake on the top level directory and I get some errors that say:
> 
> CMake Error: This project requires some variables to be set,
> and cmake can not find them.
> Please set the following variables:
> FOXCORE_LIBRARY
> FOXVIEW_LIBRARY
> 
> 
> All those are libraries that are built during the build process so of
> course with a clean build cmake can not find them because they are not
> built yet. So, how do I tell cmake that those libraries will be there?

You don't need to find libraries built by CMake in the same project.
Just reference them by their logical target name:

# Fox/Core/CMakeLists.txt
ADD_LIBRARY(FoxCore ...)

# Fox/CMakeLists.txt
ADD_EXECUTABLE(Fox ...)
TARGET_LINK_LIBRARIES(Fox FoxCore)

-Brad