ldconfig(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILES | SEE ALSO | COLOPHON

LDCONFIG(8)             Linux Programmer's Manual            LDCONFIG(8)

NAME         top

       ldconfig - configure dynamic linker run-time bindings

SYNOPSIS         top

       /sbin/ldconfig [-nNvXV] [-f conf] [-C cache] [-r root]
       directory...
       /sbin/ldconfig -l [-v] library...
       /sbin/ldconfig -p

DESCRIPTION         top

       ldconfig creates the necessary links and cache to the most recent
       shared libraries found in the directories specified on the
       command line, in the file /etc/ld.so.conf, and in the trusted
       directories, /lib and /usr/lib (on some 64-bit architectures such
       as x86-64, /lib and /usr/lib are the trusted directories for
       32-bit libraries, while /lib64 and /usr/lib64 are used for 64-bit
       libraries).

       The cache is used by the run-time linker, ld.so or ld-linux.so.
       ldconfig checks the header and filenames of the libraries it
       encounters when determining which versions should have their
       links updated.

       ldconfig will attempt to deduce the type of ELF libraries (i.e.,
       libc5 or libc6/glibc) based on what C libraries, if any, the
       library was linked against.

       Some existing libraries 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 used only for those ELF libraries which
       we can not work out.  The format is "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.
       ldconfig should normally be run by the superuser as it may
       require write permission on some root owned directories and
       files.

       Note that ldconfig will only look at files that are named
       lib*.so* (for regular shared objects) or ld-*.so* (for the
       dynamic loader itself).  Other files will be ignored.  Also,
       ldconfig expects a certain pattern to how the symlinks are set
       up, like this example, where the middle file (libfoo.so.1 here)
       is the SONAME for the library:

           libfoo.so -> libfoo.so.1 -> libfoo.so.1.12

       Failure to follow this pattern may result in compatibility issues
       after an upgrade.

OPTIONS         top

       -c fmt, --format=fmt
              (Since glibc 2.2) Cache format to use: old, new, or
              compat.  Since glibc 2.32, the default is new.  Before
              that, it was compat.

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

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

       -i, --ignore-aux-cache
              (Since glibc 2.7) Ignore auxiliary cache file.

       -l     (Since glibc 2.2) Library mode.  Manually link individual
              libraries.  Intended for use by experts only.

       -n     Process only the directories specified on the command
              line.  Don't process the trusted directories, 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.

       -p, --print-cache
              Print the lists of directories and candidate libraries
              stored in the current cache.

       -r root
              Change to and use root as the root directory.

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

       -V, --version
              Print program version.

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

FILES         top

       /lib/ld.so
              Run-time linker/loader.
       /etc/ld.so.conf
              File containing a list of directories, one per line, 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, as well as those
              found in the trusted directories.

SEE ALSO         top

       ldd(1), ld.so(8)

COLOPHON         top

       This page is part of release 5.11 of the Linux man-pages project.
       A description of the project, information about reporting bugs,
       and the latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

GNU                            2021-03-22                    LDCONFIG(8)

Pages that refer to this page: dpkg-divert(1)ldd(1)dlopen(3)rtld-audit(7)ld.so(8)sln(8)