ldd(1)
NAME
ldd - print shared object dependencies
SYNOPSIS
ldd [option]... file...
DESCRIPTION
ldd prints the shared objects (shared libraries) required by each
program or shared object specified on the command line. An example of
its use and output is the following:
$ ldd /bin/ls
linux-vdso.so.1 (0x00007ffcc3563000)
libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f87e5459000)
libcap.so.2 => /lib64/libcap.so.2 (0x00007f87e5254000)
libc.so.6 => /lib64/libc.so.6 (0x00007f87e4e92000)
libpcre.so.1 => /lib64/libpcre.so.1 (0x00007f87e4c22000)
libdl.so.2 => /lib64/libdl.so.2 (0x00007f87e4a1e000)
/lib64/ld-linux-x86-64.so.2 (0x00005574bf12e000)
libattr.so.1 => /lib64/libattr.so.1 (0x00007f87e4817000)
libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f87e45fa000)
In the usual case, ldd invokes the standard dynamic linker (see
ld.so(8)) with the LD_TRACE_LOADED_OBJECTS environment variable set to
1. This causes the dynamic linker to inspect the program's dynamic
dependencies, and find (according to the rules described in ld.so(8))
and load the objects that satisfy those dependencies. For each
dependency, ldd displays the location of the matching object and the
(hexadecimal) address at which it is loaded. (The linux-vdso and ld-
linux shared dependencies are special; see vdso(7) and ld.so(8).)
Security
Be aware that in some circumstances (e.g., where the program specifies
an ELF interpreter other than ld-linux.so), some versions of ldd may
attempt to obtain the dependency information by attempting to directly
execute the program (which may lead to the execution of whatever code
is defined in the program's ELF interpreter, and perhaps to execution
of the program itself). Thus, you should never employ ldd on an
untrusted executable, since this may result in the execution of
arbitrary code. A safer alternative when dealing with untrusted
executables is:
$ objdump -p /path/to/program | grep NEEDED
OPTIONS
--version
Print the version number of ldd.
-v, --verbose
Print all information, including, for example, symbol versioning
information.
-u, --unused
Print unused direct dependencies. (Since glibc 2.3.4.)
-d, --data-relocs
Perform relocations and report any missing objects (ELF only).
-r, --function-relocs
Perform relocations for both data objects and functions, and
report any missing objects or functions (ELF only).
--help Usage information.
BUGS
ldd does not work on a.out shared libraries. ldd does not work with some extremely old a.out programs which were built before ldd support was added to the compiler releases. If you use ldd on one of these programs, the program will attempt to run with argc = 0 and the results will be unpredictable.
SEE ALSO
pldd(1), sprof(1), ld.so(8), ldconfig(8)
COLOPHON
This page is part of release 4.09 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
2016-07-17 LDD(1)
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