/sbin/ldconfig - configure dynamic linker run time bindings
/sbin/ldconfig [ -nNvXV ] [ -f conf ] [ -C cache ] [ -r root ] direc_tory
/sbin/ldconfig -l [ -v ] library ...
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). The cache is used by the run-time linker, ld.so or ld_linux.so. ldconfig checks the header and file names of the libraries it encounters when determining which versions should have their links updated.
ldconfig will attempt to deduce the type of ELF libs (ie. libc5 or libc6/glibc) based on what C libs, if any, the library was linked against. Therefore, when making dynamic libraries, it is wise to explicitly link against libc (use -lc).
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 “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.
Table of Contents