ldconfig - configure dynamic linker run-time bindings
] [-f conf
] [-r root
creates the necessary links and cache to the most recent shared
libraries found in the directories specified on the command line, in the file
, and in the trusted directories, /lib
(on some 64-bit architectures such as x86-64, /lib
are the trusted directories for 32-bit libraries, while
are used for 64-bit libraries).
The cache is used by the run-time linker, ld.so
checks the header and filenames of the libraries it encounters
when determining which versions should have their links updated.
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
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
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
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
- -c fmt, --format=fmt
- (Since glibc 2.2) Cache format to use: old, new, or
- -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.
- (Since glibc 2.2) Library mode. Manually link individual libraries.
Intended for use by experts only.
- Process only the directories specified on the command line. Don't process
the trusted directories, nor those specified in /etc/ld.so.conf.
- Don't rebuild the cache. Unless -X is also specified, links are
- -p, --print-cache
- Print the lists of directories and candidate libraries stored in the
- -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.
- Don't update links. Unless -N is also specified, the cache is still
- Run-time linker/loader.
- File containing a list of directories, one per line, in which to search
- 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