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 directories specified on the com
mand 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 symbolic 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 architec
tures 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 directo
ries 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.
fied, 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, newline, 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
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.
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