[CMake] Static linking and find_library

[S. Levent Yilmaz]

On Wed, May 13, 2009 at 4:09 PM, Brad King <brad.king at kitware.com> wrote:

> S. Levent Yilmaz wrote:
>
>> How can one enforce static linkage on a per platform basis (not the whole
>> project)? In other words, what setting can we insert into a toolchain file <
>> http://www.vtk.org/Wiki/CMake_Cross_Compiling> to make this possible?
>>
>> Let me identify a problem here with find_library(). Here is a repeatable
>> scenario; take the following 3 line CMakeLists.txt:
>> project( foo CXX )
>> cmake_minimum_required(VERSION 2.6)
>> find_library( FOO_LIBRARY foo ENV LD_LIBRARY_PATH )
>>
>                                ^^^^^^^^^^^^^^^^^^^
> This is almost certainly a bad idea.  The find_library command already
> provides lots of customization features.  Seeits documentation.


Don't get hang up on this, it is just an example (although I'd really love
to hear you describe why it is a bad idea, and pls dont' rtfm me -- no
rhetoric intended). That said, a simple find_library( FOO_LIBRARY foo )
won't find libfoo.a since libfoo is not at some standard location, as is
usually the case with cross compiling; that is, unless one sets a proper
CMAKE_FIND_ROOT_PATH for a given system.. and we're back to this being a
simple example.. (And yes, I was referring to cross compiling scenarios
throughout; sorry if that wasn't clear enough in my post).


> Also, if you're trying to build static libs then why search in dynamic
> loader paths for libraries?
>

Because static libs are usually under the same directory as dynamic libs.
And dynamic libs ARE installed by the administrator, even though users
aren't supposed to use them. I can dwell more on this point, but rather not.
Let's just say these are the kind of systems I have to deal with..


> Your file sets CMAKE_FIND_LIBRARY_SUFFIXES but CMake loads the module
> CMakeGenericSystem.cmake *after* the toolchain file and changes it back
> to putting .so in the list.  The toolchain file is just supposed to
> specify some very basic information which triggers loading of platform-
> specific configuration.


I see. that's good to know. looking back at the wiki on cross compiling,
this info is indeed there. I just didn't realize the
CMakeGenericSystem.cmake is part of the distribution already.. anyways.


-- Levent
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.cmake.org/pipermail/cmake/attachments/20090513/6809ec42/attachment-0001.htm>