ldconfig
ldconfig(8) ldconfig(8)
NAME
ldconfig - configure dynamic linker run-time bindings
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.
-r root
Change to and use root as the root directory.
-l Library mode. Manually link individual libraries. Intended for
use by experts only.
-p --print-cache
Print the lists of directories and candidate libraries stored in
the current 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)
