ld.so, ld-linux.so* - dynamic linker/loader
ld.so loads the shared libraries needed by a program, prepares the program to run, and
then runs it. Unless explicitly specified via the -static option to ld during compila-
tion, all Linux programs are incomplete and require further linking at run time.
The necessary shared libraries needed by the program are searched for in the following
o Using the DT_RPATH dynamic section attribute of the binary if present and DT_RUN-
PATH attribute does not exist.
o Using the environment variable LD_LIBRARY_PATH . Except if the executable is a
setuid/setgid binary, in which case it is ignored.
o Using the DT_RUNPATH dynamic section attribute of the binary if present.
o From the cache file /etc/ld.so.cache which contains a compiled list of candidate
libraries previously found in the augmented library path. If, however, the binary
was linked with -z nodeflib linker option, libraries in the default library paths
o In the default path /lib, and then /usr/lib. If the binary was linked with -z
nodeflib linker option, this step is skipped.
The dynamic linker can be run either indirectly through running some dynamically linked
program or library (in which case no command line options to the dynamic linker can be
passed and the dynamic linker which is stored in the .interp section of the program is
executed) or directly by running:
/lib/ld-linux.so.* [OPTIONS] [PROGRAM [ARGUMENTS]]
COMMAND LINE OPTIONS
--list List all dependencies and how they are resolved.
Verify that program is dynamically linked and this dynamic linker can handle it.
Override LD_LIBRARY_PATH environment variable setting (see below).
Ignore RPATH and RUNPATH information in object names in LIST.
A colon-separated list of directories in which to search for ELF libraries at exe-
cution-time. Similar to the PATH environment variable.
A whitespace-separated list of additional, user-specified, ELF shared libraries to
be loaded before all others. This can be used to selectively override functions in
other shared libraries. For setuid/setgid ELF binaries, only libraries in the
standard search directories that are also setuid will be loaded.
If set to non-empty string, causes the program to list its dynamic library depen-
dencies, as if run by ldd, instead of running normally.
If set to non-empty string, causes the dynamic linker to resolve all symbols at
program startup instead of deferring function call resolval to the point when they
are first referenced.
If set to non-empty string, warn about unresolved symbols.
Output verbose debugging information about the dynamic linker. If set to all
prints all debugging information it has, if set to help prints a help message about
which categories can be specified in this environment variable.
File where LD_DEBUG output should be fed into, default is standard output.
LD_DEBUG_OUTPUT is ignored for setuid/setgid binaries.
If set to non-empty string, output symbol versioning information about the program
if querying information about the program (ie. either LD_TRACE_LOADED_OBJECTS has
been set, or --list or --verify options have been given to the dynamic linker).
/lib/ld-linux.so.* ELF dynamic linker/loader
File containing a compiled list of directories in which to search for libraries and
an ordered list of candidate libraries.
File containing a whitespace separated list of ELF shared libraries to be loaded
before the program. libraries and an ordered list of candidate libraries.
Roland McGrath, Ulrich Drepper and others. This man page is derived from libc 5 ld.so
30 October 2000 ld.so(8)