[CMake] packaging configuration files

[James C. Sutherland]

Brad, thanks for the feedback.  See comments below.

On Nov 10, 2009, at 11:30 AM, Brad King wrote:

> James C. Sutherland wrote:
>> The library I am building pulls in several other libraries (MPI, BLAS, Boost, etc).  I would like any down-stream apps that use my library to automatically be able to include any appropriate header files and link to appropriate third-party libraries that were included in my library.
> 
> Ah, I see the difference.  I was thinking about link dependencies of
> libraries that you build.  You were talking about package-level deps.
> 
>> I have the following in my Config file:
>> --------------- <snip> ---------------
>> set( ExprLib_FOUND 1 )
> 
> This is not necessary.  The find_package command automatically sets
> this when it locates the config file.
> 
>> set( ExprLib_INCLUDE_DIR @ExprLib_INCLUDE@ )
>> set( ExprLib_TPL_INCLUDE_DIRS @TPL_INCLUDE_DIRS@ )
> 
> This looks fine.  Currently we have no builtin way to express
> usage requirements.  Automatic dependency propagation only works
> for linking.
> 
>> include( @CMAKE_INSTALL_PREFIX@/lib/expression/ExprLib.cmake )
> 
> Is ExprLib.cmake produced bin install(EXPORT)?
> 

Yes.

>> set( ExprLib_LIBRARIES
>>   @CMAKE_INSTALL_PREFIX@/lib/expression/@ExprInstallLib@
>>   @TPL_LIBRARIES@
>>   )
> 
> This should not be needed.  Applications that did
> 
>  find_package(ExprLib)
> 
> should be able to do
> 
>  target_link_libraries(myapp ExprLib)
> 
> and get all the dependencies automatically.  The install(EXPORT)
> command should have put the necessary information in ExprLib.cmake
> (or one of the files it includes).  It defines an IMPORTED target
> called "ExprLib" and sets properties that tell CMake how to link
> to it.

Thanks.  To be clear, it only works if I use

	set( ExprLib_LIBRARIES @TPL_LIBRARIES@ )

because otherwise I have no way of propagating the dependents of ExprLib downstream.  It is true that CMake will add the ExprLib library as a "target" that can be used internally in downstream projects, but the other third-party libraries that ExprLib requires can only be propagated "manually" - right?