[CMake] find_library and caching

[Lucas Soltic]

Le 15 juin 2014 à 20:19, Nils Gladitz <nilsgladitz at gmail.com> a écrit :

> On 15.06.2014 19:33, Lucas Soltic wrote:
>> I use a FindSomeLib.cmake script for my project, for which there is a variable (let's call it LINK_STATIC) to define if one wants to link 	against SomeLib statically. The default is to look for dynamic libraries.
>> 
>> The issue is that when first running CMake's configure, the user may have forgotten to set LINK_STATIC, so the script finds the dynamic version of SomeLib and set a cache entry for it. Then in CMake's GUI the user realizes he wants static linking so he sets the LINK_STATIC flag, but at this point find_library has already cached the result and won't look again for static version of SomeLib.
>> 
>> This ends up with the user thinking he's using static linking, which is not what's happening.
>> I saw in CMake's doc that in order to let find_library search again, I'd need to clear the library entry it has found. But if I do this at each CMake configure run, it removes the interest of the cache.
>> 
>> Would anyone know about the preferred way to fix this caching issue?
>> I would be really grateful :)
>> 
> 
> Perhaps you could use distinct cache variables for static and shared libraries.
> 
> e.g.
> 
> find_library(FOO_STATIC_LIBRARY ...)
> find_library(FOO_SHARED_LIBRARY ...)
> 
> set(FOO_LIBRARIES "")
> 
> if(FOO_LINK_STATIC)
>    list(APPEND FOO_LIBRARIES ${FOO_STATIC_LIBRARY})
> else()
>    list(APPEND FOO_LIBRARIES ${FOO_SHARED_LIBRARY})
> endif()
> 
> Nils

Oh my… really interesting idea! Thanks!!

Lucas