.\"	$NetBSD: ldd.1,v 1.18 2009/09/07 20:06:21 wiz Exp $
.\"
.\" Copyright (c) 1998 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Paul Kranenburg.
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.Dd September 7, 2009
.Dt LDD 1
.Os
.Sh NAME
.Nm ldd
.Nd list dynamic object dependencies
.Sh SYNOPSIS
.Nm
.Op Fl o
.Op Fl f Ar format
.Ar program ...
.Sh DESCRIPTION
.Nm
displays all shared objects that are needed to run the given program.
Contrary to
.Xr nm 1 ,
the list includes
.Dq indirect
dependencies that are the result of needed shared objects which themselves
depend on yet other shared objects.
Zero, one or two
.Fl f
options may be given.
The argument is a format string passed to
.Xr rtld 1
and allows customization of
.Nm ldd Ns 's
output.
The first format argument is used for library objects and defaults to
.Qq "\et-l%o.%m =\*[Gt] %p\en" .
The second format argument is used for non-library objects and defaults to
.Qq "\et%o =\*[Gt] %p\en" .
.Pp
These arguments are interpreted as format strings a la
.Xr printf 3
to customize the trace output and allow
.Nm
to be operated as a filter more conveniently.
The following conversions can be used:
.Bl -tag -width xxxx
.It \&%a
The main program's name
.Po also known as
.Dq __progname
.Pc .
.It \&%A
The value of the environment variable
.Ev LD_TRACE_LOADED_OBJECTS_PROGNAME
in a.out and the program name from the argument vector from elf.
.It \&%o
The library name.
.It \&%m
The library's major version number.
.It \&%n
The library's minor version number (a.out only, ignored in elf).
.It \&%p
The full pathname as determined by
.Nm rtld Ns 's
library search rules.
.It \&%x
The library's load address
.El
.Pp
Additionally,
.Sy \en
and
.Sy \et
are recognized and have their usual meaning.
.Pp
The
.Fl o
option is an alias for
.Fl f
.Ar \&%a:-l\&%o.\&%m =\*[Gt] \&%p\en ,
which makes
.Nm
behave analogously to
.Ic nm Fl o .
.Sh SEE ALSO
.Xr ld 1 ,
.Xr ld.elf_so 1 ,
.Xr nm 1 ,
.Xr rtld 1
.Sh HISTORY
A
.Nm
utility first appeared in SunOS 4.0, it appeared in its current form
in
.Nx 0.9a .
.Sh BUGS
The
a.out
.Nm
actually runs the program it has been requested to analyze which in specially
constructed environments can have security implications.