[CMake] How to install headers in a library

[Giampiero Gabbiani]

In data domenica 28 febbraio 2010 11:50:20, Michael Wild ha scritto:
: > On 28. Feb, 2010, at 11:09 , Hendrik Sattler wrote:
> > Am Sonntag 28 Februar 2010 10:31:57 schrieb Giampiero Gabbiani:
> >> Hi all,
> >> I like very much the simplicity of cmake in comparison with the classic
> >> autotools framework, but still I have two questions concerning the
> >> porting of a Linux based project under cmake:
> >>
> >> 1) when defining a library (shared or static) as a project target , I
> >> expected that cmake would understand the architecture of the host
> >> machine and install conseguently the libraries (.so or .a) in the
> >> correct /lib or /lib64 path. Instead I noticed that I have to explicity
> >> set the destination path
> >>
> >> install(TARGETS <static library name> ARCHIVE DESTINATION lib64)
> >> install(TARGETS <shared object name> LIBRARY DESTINATION lib64)
> >>
> >> This works well on my machine (a 64 bit system) but of course will not
> >> work if anyone want to install on a 32 bit system.
> >>
> >> So ... is there a way in order to let cmake automatically install on the
> >> correct path according with the hosting system architecture?
> >>
> >> 2) together with the resulting binaries libs (both archive and library)
> >> I want to install also the corrisponding header(s) in /usr/local/include
> >> path...how is it possible to do that?
> >
> > You could use a variable to represent the directory. This would depend on
> > the existence of lib64/ (not all have this as directory, on Debian it's
> > just a compatibility link to lib/) and on SIZEOF_VOID_P being 8:
> > set (LIBRARY_INSTALL_DIR lib)
> > if (EXISTS "${CMAKE_INSTALL_PREFIX}/lib32/" AND CMAKE_SIZEOF_VOID_P EQUAL
> > 4) set (LIBRARY_INSTALL_DIR lib32)
> > elif (EXISTS "${CMAKE_INSTALL_PREFIX}/lib64/" AND CMAKE_SIZEOF_VOID_P
> > EQUAL 8) set (LIBRARY_INSTALL_DIR lib64)
> > endif ()
> >
> > Or let the user set it.
> >
> > HS
> 
> Such decisions I often handle like this:
> 
> - compute a sensible default, as Hendrik showed above.
> - use that default to set a cache variable
> - let the user override the default using the cache variables
> 
> In above example this would be:
> 
> # compute default library install dir
> set (_DEFAULT_LIBRARY_INSTALL_DIR lib)
> if (EXISTS "${CMAKE_INSTALL_PREFIX}/lib32/" AND CMAKE_SIZEOF_VOID_P EQUAL
>  4) set (_DEFAULT_LIBRARY_INSTALL_DIR lib32)
> elif (EXISTS "${CMAKE_INSTALL_PREFIX}/lib64/" AND CMAKE_SIZEOF_VOID_P EQUAL
>  8) set (_DEFAULT_LIBRARY_INSTALL_DIR lib64)
> endif ()
> # the library install dir
> set(LIBRARY_INSTALL_DIR "${_DEFAULT_LIBRARY_INSTALL_DIR}" CACHE PATH
>  "Installation directory for libraries") # make the library install dir an
>  absolute path (can be important e.g. when using CONFIGURE_FILE to embed #
>  the library installation directory into a file)
> if(NOT IS_ABSOLUTE "${LIBRARY_INSTALL_DIR}")
>   set(LIBRARY_INSTALL_DIR "${CMAKE_INSTALL_PREFIX}/${LIBRARY_INSTALL_DIR}")
> endif()
> 
> 
> Of course, you can extend the logic for the default selection to handle
>  particularities of other platforms, such as Windows.
> 
> HTH
> 
> Michael
> 
Great!
Many thanks!
Giampiero