[CMake] A small philosophical problem

[Bill Hoffman]

Carminati Federico wrote:
> Hello,
>     I want to be able to build optionally static libs for my project. I 
> have no problem to add custom targets and dependencies, this all works 
> nicely. However I want to be able to install them if needed. So I define 
> an installation rule and I label it as optional, as these files may or 
> may not exist. cmake complains with the following message
> 
> WARNING: Target "TTherminator_a" has EXCLUDE_FROM_ALL set and will not 
> be built by default but an install rule has been provided for it.  CMake 
> does not define behavior for this case.
> 
> I believe that this warning is justified if I do not lable the component 
> as OPTIONAL, however if it is labelled as optional, the behaviour IS 
> welll defined. The component is not there and it will not be installed. 
> So I believe that in case of optional install targets the warning should 
> not be there. BEst,
> 

It would be more the "cmake way" to use a cmake time option to build or 
not build the optional library.

option(BUILD_THERMINATOR " build static TTherminator library")
if(BUILD_THERMINATOR)
   add_library(TTherminator_a STATIC ...)
endif(BUILD_THERMINATOR)

-Bill