[CMake] Problem with LINK_DIRECTORIES

[Michael Wild]

On 11/14/2011 03:36 PM, Robert Dailey wrote:
> On Mon, Nov 14, 2011 at 6:42 AM, Michael Wild <themiwi at gmail.com
> <mailto:themiwi at gmail.com>> wrote:
> 
>     Hi Arun
> 
>     Consider LINK_DIRECTORIES to be obsolete and to be avoided at all cost.
> 
> 
> I don't really agree with this advice. There are circumstances where
> link_directories() is absolutely necessary, so advocating to completely
> avoid it isn't really a one size fits all scenario.

Pray tell, what scenario would that be? I'm really curious, because I
can't think of any...

> 
> What I've done is make sure that link_directories() is called from a
> parent level directory, so that all projects inherit the directories. In
> cases where you do not have a hierarchy setup like this, then call
> link_directories() once with the same directories before each call to
> add_executable, add_library, etc.
> 
> Also one unrelated note, but static libraries do not require any
> dependencies to be linked in when it is built. You only need your third
> party libraries in your shared library or executable that links against
> the static library in question.

The OP is talking about such a setup

a/CMakelists.txt:
----------------
add_library(a STATIC a.c)
# a uses foo internally, but doesn't expose this fact in its interface.
# clients of a should not need to know about a's implementation details,
# which is why we declare this dependency here and let CMake handle the
# rest.
target_link_libraries(a foo)

b/CMakeLists.txt
-----------------
add_executable(b b.c)
target_link_libraries(b a)


Michael