LDD(1) Linux Programmer's Manual LDD(1)
ldd - print shared library dependencies
ldd [OPTION]... FILE...
ldd prints the shared libraries required by each program or shared library specified on the command line. Security 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, which causes the linker to display the library dependencies. Be aware, however, that in some circumstances, some versions of ldd may attempt to obtain the dependency information by directly executing the program. 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
--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.
The standard version of ldd comes with glibc2. Libc5 came with an older version, still present on some systems. The long options are not supported by the libc5 version. On the other hand, the glibc2 version does not support -V and only has the equivalent --version. The libc5 version of this program will use the name of a library given on the command line as-is when it contains a '/'; otherwise it searches for the library in the standard locations. To run it on a shared library in the current directory, prefix the name with "./".
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.
This page is part of release 3.64 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. 2012-07-16 LDD(1)
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