[cmake-developers] Finding versioned libraries

[Rolf Eike Beer]

> 2012/2/15 Rolf Eike Beer <eike at sf-mail.de>:
>> Hi,
>>
>> as I found out today this construct doesn't work:
>>
>> find_library(MYLIB libfoo.so.2)
>>
>> This is because find_library will only try to access the whole path if
>> the
>> given name matches PREFIX.*SUFFIX, which is obviously not the case here.
>> My
>> simple approach on fixing this would be to also allow
>> PREFIX.*SUFFIX\..*:
>
> [...]
>> @@ -358,9 +358,17 @@ bool
>> cmFindLibraryHelper::HasValidSuffix(std::string const& name)
>
> [...]
>> Any objections?
>
> If the user does not trust find_library for checking proper extension
> then:
>    1) He could modify/append CMAKE_FIND_LIBRARY_SUFFIXES
>        in this case:
>           list(APPEND CMAKE_FIND_LIBRARY_SUFFIXES ".so.2")
>        should work.
>
>    2) He could use find_file
>
> Now if we consider this is a bug,
> then with your modification "HasValidSuffix" is ill-named since it is more
> like
> "ContainsValidSuffix" or "MatchesValidSuffix".
>
> With this modification one could now find a not-properly-installed
> library (missing links) without noticing it.

Yes, but only if he explicitely specifies the correct name. It's not that
find_library will now find libfoo.so.2 now when you do find_library(VAR
foo).

> What is your purpose here, do you want to ensure that you find a
> particular version of a lib?

FindPerlLibs.cmake queries perl for the perl library name, which is e.g.
"libperl.so.5.12.4" on my machine. And find_library is not able to find a
library given that name, even if it is perfectly valid. With this
modification is is able to get that.

Eike