[CMake] Best practices/preferred methods for linking external libraries

[Matthew LeRoy]

On 2011-12-03 14:54-0800 Alan W. Irwin wrote:
> 
> On 2011-12-03 12:42-0800 Alan W. Irwin wrote:
> 
> > On 2011-12-02 19:33-0000 Matthew LeRoy wrote:
> >> Assuming we want to just put the install tree in version control
> >> somewhere, and have ProjectB's list files reference the install tree
> >> out of version control, is writing a Find module the best way to do
> >> that?
> >
> > I don't see any way your highly unusual use case could work unless you
> > adopt a common installation prefix for projectA that everybody can use
> > on their various systems.
> 
> Hi Matt:
> 
> On second thought I got too negative about your strange use case, and to
> answer your question directly for that case, yes, with a Find module written
> for ProjectA,  then your ProjectB users can install ProjectA anywhere, and if
> they set CMAKE_LIBRARY_PATH and CMAKE_INCLUDE_PATH properly, they _should_ be
> able to get the Find module to find libraries, headers, etc., from ProjectA
> regardless of where it is installed.
> 
> That said, I am still a little surprised you are not taking the traditional
> independent software package approach for ProjectA.
> 
> Alan

Alan:

I explained a little further (hopefully clearer?) what I'm trying to accomplish
in another reply, here: http://www.cmake.org/pipermail/cmake/2011-December/047897.html.

A further clarification would be that ProjectA is not intended to be distributed
publicly on it's own at all; it will only ever be distributed as part of another
project which uses it (ProjectB, for example). Essentially, it's just an independent,
reusable sub-component that we want to develop in isolation.

Here's something like what I was envisioning with putting the binary distribution
in the source tree for ProjectB (many things omitted):

/ProjectB
|--CMakeLists.txt
|--/src
|--/test
`--/lib
   |--/bin
   |  `--libProjectA.so
   `--/include
      `--/ProjectA
         `--*ProjectA headers here*

The idea, then, would be that whenever we want B to use a new version of A,
we just drop the new .so and includes for A overtop of the existing ones in the
source tree and commit them.

So, the question is, what's the best way to get B's CMakeLists.txt files to find
and use A from within B's own source tree? A Find*.cmake module for A?

Or, do you recommend a different approach entirely?

Matt