[CMake] Fwd: Removing overkill linking

[Marcel (ASTRON)]

Op zaterdag 02-10-2010 om 19:11 uur [tijdzone +0100], schreef Paul
McEnery:
> No sure what happened to this message. I checked the list archive, and
> only half of the message appeared....
> 
> http://www.cmake.org/pipermail/cmake/2010-October/039975.html
> 
> 
> On 1 October 2010 16:40, Marcel Loose <loose at astron.nl> wrote:
> > Hi Paul,
> >
> > Probably one of the packages that you "pull in" -- dbus, dbug-glib,
> > libftdi, libglade, gtk+2, hal -- is introducing this dependency. Check
> > the different *_LIBRARIES variables and you'll probably find the fly in
> > your ointment.
> >
> > You may definitely want to look into the LINK_INTERFACE_LIBRARIES option
> > of target_link_libraries to avoid over-linking.
> >
> 
> Thanks Marcel.
> 
> I have managed to solve the issue on the shared library, however, I'm
> still having an issue with the executable being excessively linked.
> I've tried a number of different ways, but don't think I have the
> syntax right for what I'm trying to achieve.
> 
> ====================================
> # Dependencies
> find_package      (PkgConfig)
> pkg_check_modules (DBUS       REQUIRED   dbus-1>=1.2.12)
> pkg_check_modules (DBUS-GLIB  REQUIRED   dbus-glib-1>=0.80)
> pkg_check_modules (FTDI       REQUIRED   libftdi>=0.13)
> pkg_check_modules (GLADE      REQUIRED   libglade-2.0>=2.6.4)
> pkg_check_modules (GTK2       REQUIRED   gtk+-2.0>=2.16.1)
> pkg_check_modules (HAL        REQUIRED   hal>=0.5.12)
> 
> # Main config
> add_definitions(-DGLADEFILE="${CMAKE_INSTALL_PREFIX}/${sharedir}/galinette_gtk.glade")
> add_definitions(-DGALINETTE_VERSION="${GALINETTE_VERSION}")
> 
> # Include & build
> include_directories   (. ${DBUS_INCLUDE_DIRS}
> ${DBUS-GLIB_INCLUDE_DIRS} ${GLADE_INCLUDE_DIRS} ${GTK2_INCLUDE_DIRS}
> ${HAL_INCLUDE_DIRS})
> add_executable        (galinette callbacks.c callbacks.h
> galinette-gtk.c galinette_gtk.glade galinette-gtk.h hal.c hal.h
> main.c)
> add_dependencies      (galinette libgalinette)
> target_link_libraries (galinette libgalinette ${DBUS_LIBRARIES}
> ${DBUS-GLIB_LIBRARIES} ${GLADE_LIBRARIES} ${GTK2_LIBRARIES}
> ${HAL_LIBRARIES})
> target_link_libraries (galinette LINK_INTERFACE_LIBRARIES "")
> 
> # Other resources
> add_custom_target (galinette_gtk.glade)
> 
> # Install
> install (TARGETS galinette           DESTINATION ${bindir})
> install (FILES   galinette_gtk.glade DESTINATION ${sharedir})
> ====================================
> 
> From what I can gather from the lists and documentation, executables
> are handled slightly differently to libraries. To solve the library
> issue, I used the following which worked correctly:
> 
> ====================================
> # Dependencies
> find_package          (PkgConfig)
> pkg_check_modules     (FTDI  REQUIRED  libftdi>=0.13)
> 
> # Include & build
> include_directories   (. ${FTDI_INCLUDE_DIRS})
> add_library           (libgalinette SHARED device.c error.c firmware.c
> flash.c libgalinette.h libgalinette-private.h)
> set_target_properties (libgalinette PROPERTIES PREFIX ""
> LINK_INTERFACE_LIBRARIES "" SOVERSION 0)
> target_link_libraries (libgalinette ${FTDI_LIBRARIES})
> 
> # Install
> install (TARGETS libgalinette LIBRARY DESTINATION ${libdir})
> ====================================
> 
> set_target_properties doesn't seem to work on executables though.
> 
> Hopefully someone who knows a bit more than I do will be able to spot
> what I'm doing wrong...
> 
> Kind regards,
> Paul.
Hi Paul,

How exactly did you check which libraries your executable are linked to.
If on Linux, you should use 'readelf -d', not 'ldd'. The latter will
also show all transitive dependencies, which is useful, of course, when
you want to know which libraries are needed. However, 'ldd' gives you a
false impression w.r.t. overlinking.

Best regards,
Marcel Loose.