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ldconfig


SYNOPSIS

       ldconfig [OPTION...]


DESCRIPTION

       ldconfig creates the necessary links and cache (for use by the run-time
       linker, ld.so) to the most recent shared libraries found in the  direc-
       tories  specified on the command line, in the file /etc/ld.so.conf, and
       in the trusted directories (/usr/lib and /lib).   ldconfig  checks  the
       header  and  file names of the libraries it encounters when determining
       which versions should have their links updated.  ldconfig ignores  sym-
       bolic links when scanning for libraries.

       ldconfig  will  attempt to deduce the type of ELF libs (ie. libc 5.x or
       libc 6.x (glibc)) based on what C libraries  if  any  the  library  was
       linked  against, therefore when making dynamic libraries, it is wise to
       explicitly link against libc (use -lc).  ldconfig is capable of storing
       multiple  ABI  types  of libraries into a single cache on architectures
       which allow native running of multiple ABIs, like  ia32/ia64/x86_64  or
       sparc32/sparc64.

       Some  existing  libs  do  not  contain  enough information to allow the
       deduction of their type,  therefore  the  /etc/ld.so.conf  file  format
       allows  the  specification  of an expected type.  This is only used for
       those ELF libs which we can not work  out.  The  format  is  like  this
       "dirname=TYPE",  where type can be libc4, libc5 or libc6.  (This syntax
       also works on the command line).  Spaces are not allowed. Also see  the
       -p option.

       Directory  names  containing  an = are no longer legal unless they also
       have an expected type specifier.

       ldconfig should normally be run by the super-user  as  it  may  require
       write  permission  on some root owned directories and files. If you use
       -r option to change the root directory, you don’t have to be super-user
       though as long as you have sufficient right to that directory tree.


OPTIONS

       -v --verbose
              Verbose  mode.   Print  current version number, the name of each
              directory as it is scanned and any links that are created.

       -n     Only process directories specified on the command  line.   Don’t
              process  the  trusted  directories (/usr/lib and /lib) nor those
              specified in /etc/ld.so.conf.  Implies -N.

       -N     Don’t rebuild the cache.  Unless -X is also specified, links are
              still updated.

       -X     Don’t  update  links.  Unless -N is also specified, the cache is
              still rebuilt.

       -f conf
              Use conf instead of /etc/ld.so.conf.

       -C cache
              Use cache instead of /etc/ld.so.cache.

       -c --format=FORMAT
              Use FORMAT for the cache file. Choices are old, new  and  compat
              (the default).

       -? --help --usage
              Print usage information.

       -V --version
              Print version and exit.


EXAMPLES

              # /sbin/ldconfig -v
       will  set  up the correct links for the shared binaries and rebuild the
       cache.
              # /sbin/ldconfig -n /lib
       as root after the installation of a new shared  library  will  properly
       update the shared library symbolic links in /lib.


FILES

       /lib/ld-linux.so.*  execution time linker/loader
       /etc/ld.so.conf     File  containing  a list of colon, space, tab, new-
                           line, or comma spearated directories  in  which  to
                           search for libraries.
       /etc/ld.so.cache    File  containing an ordered list of libraries found
                           in the directories  specified  in  /etc/ld.so.conf.
                           This  file  is not in human readable format, and is
                           not intended to be edited.
       lib*.so.version     shared libraries


SEE ALSO

       ldd(1), ld.so(8).


BUGS

       ldconfig, being a user process, must be run manually and has  no  means
       of  dynamically  determining  and relinking shared libraries for use by
       ld.so when a new shared library is installed.


AUTHORS

       Andreas Jaeger.  Manual page written by David Engel and Mitch  D’Souza.

                                30 October 2000                    ldconfig(8)

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