ldconfig(8) — Linux manual page


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

       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

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

       Failure to follow this pattern may result in compatibility issues af‐
       ter 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

       -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

              Run-time linker/loader.
              File containing a list of directories, one per line, in which
              to search for libraries.
              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 5.09 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

GNU                              2020-06-09                      LDCONFIG(8)

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