1LDCONFIG(8) Linux Programmer's Manual LDCONFIG(8)
2
6 ldconfig - configure dynamic linker run-time bindings
7
9 /sbin/ldconfig [-nNvXV] [-f conf] [-C cache] [-r root] directory...
10 /sbin/ldconfig -l [-v] library...
11 /sbin/ldconfig -p
12
14 ldconfig creates the necessary links and cache to the most recent
15 shared libraries found in the directories specified on the command
16 line, in the file /etc/ld.so.conf, and in the trusted directories, /lib
17 and /usr/lib (on some 64-bit architectures such as x86-64, /lib and
18 /usr/lib are the trusted directories for 32-bit libraries, while /lib64
19 and /usr/lib64 are used for 64-bit libraries).
20 The cache is used by the run-time linker, ld.so or ld-linux.so. ldcon‐
22 fig checks the header and filenames of the libraries it encounters when
23 determining which versions should have their links updated.
24 ldconfig will attempt to deduce the type of ELF libraries (i.e., libc5
26 or libc6/glibc) based on what C libraries, if any, the library was
27 linked against.
28 Some existing libraries do not contain enough information to allow the
30 deduction of their type. Therefore, the /etc/ld.so.conf file format
31 allows the specification of an expected type. This is used only for
32 those ELF libraries which we can not work out. The format is
33 "dirname=TYPE", where TYPE can be libc4, libc5, or libc6. (This syntax
34 also works on the command line.) Spaces are not allowed. Also see the
35 -p option. ldconfig should normally be run by the superuser as it may
36 require write permission on some root owned directories and files.
37 Note that ldconfig will only look at files that are named lib*.so* (for
39 regular shared objects) or ld-*.so* (for the dynamic loader itself).
40 Other files will be ignored. Also, ldconfig expects a certain pattern
41 to how the symlinks are set up, like this example, where the middle
42 file (libfoo.so.1 here) is the SONAME for the library:
43 libfoo.so -> libfoo.so.1 -> libfoo.so.1.12
45 Failure to follow this pattern may result in compatibility issues after
47 an upgrade.
48
50 -c fmt, --format=fmt
51 (Since glibc 2.2) Cache format to use: old, new, or compat.
52 Since glibc 2.32, the default is new. Before that, it was com‐
53 pat.
54 -C cache
56 Use cache instead of /etc/ld.so.cache.
57 -f conf
59 Use conf instead of /etc/ld.so.conf.
60 -i, --ignore-aux-cache
62 (Since glibc 2.7) Ignore auxiliary cache file.
63 -l (Since glibc 2.2) Library mode. Manually link individual li‐
65 braries. Intended for use by experts only.
66 -n Process only the directories specified on the command line.
68 Don't process the trusted directories, nor those specified in
69 /etc/ld.so.conf. Implies -N.
70 -N Don't rebuild the cache. Unless -X is also specified, links are
72 still updated.
73 -p, --print-cache
75 Print the lists of directories and candidate libraries stored in
76 the current cache.
77 -r root
79 Change to and use root as the root directory.
80 -v, --verbose
82 Verbose mode. Print current version number, the name of each
83 directory as it is scanned, and any links that are created.
84 Overrides quiet mode.
85 -V, --version
87 Print program version.
88 -X Don't update links. Unless -N is also specified, the cache is
90 still rebuilt.
91
93 /lib/ld.so
94 Run-time linker/loader.
95 /etc/ld.so.conf
96 File containing a list of directories, one per line, in which to
97 search for libraries.
98 /etc/ld.so.cache
99 File containing an ordered list of libraries found in the direc‐
100 tories specified in /etc/ld.so.conf, as well as those found in
101 the trusted directories.
102
104 ldd(1), ld.so(8)
105
107 This page is part of release 5.10 of the Linux man-pages project. A
108 description of the project, information about reporting bugs, and the
109 latest version of this page, can be found at
110 https://www.kernel.org/doc/man-pages/.
111GNU 2020-06-09 LDCONFIG(8)