ldd(1) — Linux manual page


LDD(1)                    Linux Programmer's Manual                   LDD(1)

NAME         top

       ldd - print shared object dependencies

SYNOPSIS         top

       ldd [option]... file...

DESCRIPTION         top

       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).)

       Be aware that in some circumstances (e.g., where the program speci‐
       fies 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 per‐
       haps to execution of the program itself.  (In glibc versions before
       2.27, the upstream ldd implementation did this for example, although
       most distributions provided a modified version that did not.)

       Thus, you should never employ ldd on an untrusted executable, since
       this may result in the execution of arbitrary code.  A safer alterna‐
       tive when dealing with untrusted executables is:

           $ objdump -p /path/to/program | grep NEEDED

       Note, however, that this alternative shows only the direct dependen‐
       cies of the executable, while ldd shows the entire dependency tree of
       the executable.

OPTIONS         top

              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         top

       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         top

       pldd(1), sprof(1), ld.so(8), ldconfig(8)

COLOPHON         top

       This page is part of release 5.08 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

                                 2019-03-06                           LDD(1)

Pages that refer to this page: pldd(1)sprof(1)uselib(2)dlclose(3)dl_iterate_phdr(3)dlmopen(3)dlopen(3)babeltrace2-filter.lttng-utils.debug-info(7)rtld-audit(7)vdso(7)ldconfig(8)ld-linux(8)ld-linux.so(8)ld.so(8)prelink(8)