ldconfig
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 filenames of the libraries it encounters when determining which versions should have their links updated.[1]
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).[1]
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.[1]
Documentation
- man 8 'ldconfig' [EN]
Syntax
ldconfig [PARAMETER ...] [DIRECTORY ...]
ldconfig -l [-v] LIBRARY [...]
ldconfig -p
Parameters
- -p
- Print the lists of directories and candidate libraries stored in the current cache.