LDCONFIG(8) | System Manager's Manual | LDCONFIG(8) |
ldconfig
—
configure the shared library cache
ldconfig |
[-mRrsUv ] [path ...] |
ldconfig
is used to prepare a set of
“hints” for use by the run-time linker
ld.so(1) to facilitate quick lookup of
shared libraries available in multiple directories. It scans a set of
built-in system directories and any directories
specified on the command line (in the given order) looking for shared
libraries and stores the results in the file
/var/run/ld.so.hints to forestall the overhead that
would otherwise result from the directory search operations
ld.so(1) would have to perform to load the
required shared libraries.
The shared libraries so found will be automatically available for loading if needed by the program being prepared for execution. This obviates the need for storing search paths within the executable.
The LD_LIBRARY_PATH
environment variable
can be used to override the use of directories (or the order thereof) from
the cache or to specify additional directories where shared libraries might
be found. LD_LIBRARY_PATH
is a ‘:’
separated list of directory paths which are searched by
ld.so(1) when it needs to load a shared
library. It can be viewed as the run-time equivalent of the
-L
switch of
ld(1).
ldconfig
is typically run as part of the
boot sequence. In addition to the built-in system directories, directories
containing shared libraries may be specified via the
shlib_dirs
variable in
/etc/rc.conf.local. See
rc.conf(8) for further information.
The following options are recognized by
ldconfig
:
-m
-U
.-R
-r
-s
-U
-m
.-v
Special care must be taken when loading shared libraries into the
address space of set-user-Id
programs. Whenever such
a program is run, ld.so(1) will only load
shared libraries from the ld.so.hints file. In
particular, the LD_LIBRARY_PATH
is not used to
search for libraries. Thus, the role of ldconfig
is
dual. In addition to building a set of hints for quick lookup, it also
serves to specify the trusted collection of directories from which shared
objects can be safely loaded. It is presumed that the set of directories
specified to ldconfig
are under control of the
system's administrator. ld.so(1) further
assists set-user-Id programs by erasing the
LD_LIBRARY_PATH
from the environment.
LD_LIBRARY_PATH
shlib_dirs
An ldconfig
utility first appeared in
SunOS 4.0. It appeared in its current form in NetBSD
0.9A.
July 4, 2016 | OpenBSD-current |