[cmake-developers] Fwd: EXPORT_NAME-genex

[Alexander Neundorf]

On Monday 20 May 2013, Daniel Pfeifer wrote:
> 2013/5/20 Brad King <brad.king at kitware.com>
> 
> > We had some recent discussion about encouraging the convention of
> > "namespace::" for imported targets, but perhaps we should reconsider
> > the value and cost.
> 
> One of CMake's most powerful features in my opionion is the way it handles
> sub-projects.
> I can take two CMake-projects, Foo and Bar, put them in my Worspace
> directory where I have a CMakeLists.txt file with the content:
> 
> add_subdirectory(Foo)
> add_subdirectory(Bar)
> 
> I can now build these two projects with the same tools and flags, which is
> extremely handy for crosscompilation.
> This works pretty well in many cases, but sometimes it breaks, because some
> projects are not "good neighbors" or they want to be the top level project.

For instance target names must (should) be unique, and using CMAKE_(SOURCE|
BINARY)_DIR is usually a bad idea in this case.

> I would like to see more projects that can be built both on their own and
> as part of a bigger workspace.
> In this case, it is important that these projects make no distincion
> whether their dependencies are part of the same workspace or not.

I think they have to.
Let's say Bar depends on the library Foo, Bar has to search for it, and fail 
if it is not present:

Bar/CMakeLists.txt:


if(NOT TARGET Foo)
  find_package(Foo REQUIRED)
else()
  set(Foo_LIBRARIES Foo)
  set(Foo_INCLUDE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}/somewhere )
endif()
...

target_link_libraries(Bar ${Foo_LIBRARIES})


How would you handle it otherwise ?

Alex