NAME

ldd — list dynamic object dependencies

SYNOPSIS

ldd	[-o] [-f format] program ...

DESCRIPTION

ldd displays all shared objects that are needed to run the given program. Contrary to nm(1), the list includes “indirect” dependencies that are the result of needed shared objects which themselves depend on yet other shared objects. Zero, one or two -f options may be given. The argument is a format string passed to rtld(1) and allows customization of ldd's output. The first format argument is used for library objects and defaults to “\t-l%o.%m => %p\n”. The second format argument is used for non-library objects and defaults to “\t%o => %p\n”.

These arguments are interpreted as format strings a la printf(3) to customize the trace output and allow ldd to be operated as a filter more conveniently. The following conversions can be used:

%a

The main program's name (also known as “__progname”).

%A

The value of the environment variable LD_TRACE_LOADED_OBJECTS_PROGNAME in a.out and the program name from the argument vector from elf.

%o

The library name.

%m

The library's major version number.

%n

The library's minor version number (a.out only, ignored in elf).

%p

The full pathname as determined by rtld's library search rules.

%x

The library's load address

Additionally, \n and \t are recognized and have their usual meaning.

The -o option is an alias for -f %a:-l%o.%m => %p\n, which makes ldd behave analogously to nm -o.

SEE ALSO

ld(1), ld.elf_so(1), nm(1), rtld(1)

HISTORY

A ldd utility first appeared in SunOS 4.0, it appeared in its current form in NetBSD 0.9a.

BUGS

The a.out ldd actually runs the program it has been requested to analyze which in specially constructed environments can have security implications.