ldconfig

ldconfig – configure dynamic linker run-time bindings

ldconfig [OPTION…]

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 command line, in the file /etc/ld.so.conf, and in the trusted directories (/usr/lib and /lib). ldconfigchecks 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 architectures which allow native running of multiple ABIs, like ia32/ia64/x86_64 or sparc32/sparc64.

/etc/ld.so.cache

ldconfig

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.