[CMake] help with FindBoost.cmake

[Tristan Carel]

On 3/31/07, kdsfinger at gmail.com <kdsfinger at gmail.com> wrote:
> On 3/31/07, Filipe Sousa <natros at gmail.com> wrote:
> > kdsfinger at gmail.com wrote:
> > > hi,
> > > I am using cmake and some library of boost on a linux box. When I use
> > > the boost::shared_ptr, everything is fine. But when I try to
> > > #include <boost/filesystem/operations.hpp>
> > > #include <boost/filesystem/path.hpp>,
> > > the cmake generates lots of "undefined reference to
> > > 'boost::filesystem::...' errors. Is there something wrong with the
> > > FindBoost.cmake? Why I still can use part of the boost like
> > > boost::shared_ptr? Thanks for help.
> > > zl2k
> >
> > most of boost are header files only, but boost filesystem has it's own
> > library that you must link against you program. that's why you have
> > undefined references.
> >
> > Filipe Sousa
> >
> >
> >
> >
> >
> > _______________________________________________
> > CMake mailing list
> > CMake at cmake.org
> > http://www.cmake.org/mailman/listinfo/cmake
> >
> >
>
> Could you give me more guidance on how to do that? Do I need to change
> the FindBoost.cmake so that let it find the boost/filesystem? Or
> should I change the CMakeList.txt? Thanks again.

You don't have to change the module. The comments at the beginning of
the module tells you that 2 variables have been set by the module
itself: ${Boost_INCLUDE_DIRS} and ${Boost_LIBRARY_DIRS}. It means that
the module is in charge to set these 2 variables, and you are the guy
who has to use them:)

Here is an example of CMakeLists.txt t to compile the `simple_ls.cc'
available in the boost filesystem documentation.
--------------------------------------------------
PROJECT(TestBoost)
FIND_PACKAGE(Boost)

INCLUDE_DIRECTORIES(${Boost_INCLUDE_DIRS})
LINK_DIRECTORIES(${Boost_LIBRARY_DIRS})

ADD_EXECUTABLE(myls simple_ls.cc)
TARGET_LINK_LIBRARIES(myls boost_filesystem)
--------------------------------------------------

the critical point is, as said Filipe above, the library must be
linked against the program, that is what the `TARGET_LINK_LIBRARIES'
does.

bye
-- 
Tristan Carel
Music with dinner is an insult both to the cook and the violinist.
http://www.tristan-carel.com