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nm(1)
NAME
nm - Name list dump of object files
SYNOPSIS
nm [-B|-P|-S] [-AabdfhnoprTVvwx] [-e|-g|-u] [-t format]
[-mangled_name_only] [-mangled_name_also] [file...]
STANDARDS
Interfaces documented on this reference page conform to industry standards
as follows:
nm: XPG4, XPG4-UNIX
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
OPTIONS
The nm command accepts both XPG4-UNIX standard options and DIGITAL
extensions.
The following options control the format of the output:
default
Prints output in OSF format.
-B [DIGITAL] Prints output in Berkeley (4.3 BSD) format. This format
produces an address or value field followed by a letter showing what
section the symbol is located in. The third and final field is the name
of the symbol.
-P Prints output in a portable (POSIX) format. This format prints lines
containing each symbol's name, type (single letter), value, and size.
-S [DIGITAL] Prints output in System V format.
The following options control the contents of the output, how sorting is
done, and how numeric values are printed. Note that the format that is in
effect influences the results of many of these options:
-A Prints the full pathname or library name of an object on each line.
-a [DIGITAL] Prints full debugging information.
-b [DIGITAL] For Berkeley (-B) format only, prints the value field in
octal. Equivalent to -t o.
-d [DIGITAL] Prints the value field in decimal. Equivalent to -t d.
-e Prints only external and static symbol information.
-g Prints only external symbol information.
-h [DIGITAL] Suppresses the printing of headers.
-n [DIGITAL] For Berkeley (-B) format, sorts all symbols by value. For
System V (-S) format, sorts external symbols by name. For other
formats, sorts all symbols by name.
-o Prints numeric values in octal (equivalent to -t o).
[DIGITAL] For Berkeley format (-B), prepends the filename to each
symbol (equivalent to -A).
-p [DIGITAL] Prints symbols in the order in which they are found in the
file.
-r [DIGITAL] Reverses the order of a value or name sort.
-T [DIGITAL] Truncates long names, inserting an asterisk (*) as the last
printed character.
-t format
Writes each numeric value in the specified format as follows:
d The offset is written in decimal. Equivalent to -d.
o The offset is written in octal. Equivalent to -o.
x The offset is written in hexadecimal. Equivalent to -x.
-u Prints only undefined symbols.
-V [DIGITAL] Prints version information on stderr.
-v Sorts output by value instead of alphabetically.
[DIGITAL] For System V format (-S), sorts external symbols by value.
-w [DIGITAL] Identifies weak symbols using an asterisk (*). For the
default, portable (-P), and Berkeley (-B) formats, the asterisk follows
the symbol type letter. For System V (-S), an additional column is
added to the end of each line containing an asterisk for weak symbols.
-x Prints numeric values in hexadecimal. Equivalent to -t x.
[DIGITAL] The DEC C++ compiler encodes type information in function,
template, variable, and virtual table names to enable type-safe linkages.
This encoding is called "name mangling." The following options can be used
to instruct the nm command to print either the original name (that is, the
demangled name), the mangled name, or both, by specifying one of the
following options. By default, nm shows the demangled names only.
-mangled_name_only
[DIGITAL] Prints only the mangled name.
-mangled_name_also
[DIGITAL] Prints both the mangled and the demangled names.
DESCRIPTION
The nm command prints formatted listings of the symbol and external
sections of an object file symbol table. A file can be an object file, an
archive library, or a shared library. If you do not specify a file, this
command assumes a.out.
The nm tool supports four output formats:
· OSF (the default)
· [DIGITAL] Berkeley 4.3 BSD (-B option)
· [DIGITAL] System V (-S option)
· Portable (-P option)
The following default behaviors are the same for all four formats:
· Sort by name
· Show external and static symbols
· Output in hexadecimal
The only exception to these defaults is that numbers in OSF format are in
decimal by default.
Each format has a distinctive output style and can influence the results of
some of the options that affect content, how sorting is done, and how
numeric values are printed, as explained in the OPTIONS section.
Output
If symbolic information is present in the input files, nm writes the
following information for each file or archive member by default:
· Symbol name
· Value of the symbol
· Symbol type
· Size associated with the symbol, if applicable
For example:
Name Value Type Size
_gp | 0000005368742016 | A | 0000000000000008
exit | 0000004831842368 | U | 0000000000000008
main | 0000004831842816 | T | 0000000000000008
For the default, portable (-P), and Berkeley (-B) formats, single
characters are used as an abbreviation for symbol types. Uppercase
characters represent external symbols, and lowercase letters represent
local symbols.
The symbol types and their abbreviations are as follows:
A External absolute
a Local absolute
B External zeroed data
b Local zeroed data
C [DIGITAL] Common
D External initialized data
d Local initialized data
E [DIGITAL] Small common
G [DIGITAL] External small initialized data
g [DIGITAL] Local small initialized data
H [DIGITAL] TLS common
J [DIGITAL] TLS initialized data
K [DIGITAL] TLS zeroed data
N [DIGITAL] Nil storage class, compiler internal usage
Q [DIGITAL] Read-only constants
q [DIGITAL] Local read-only constants
R [DIGITAL] External read-only data
r [DIGITAL] Local read-only data
S [DIGITAL] External small zeroed data
s [DIGITAL] Local small zeroed data
T External text
t Local text
U External undefined
V [DIGITAL] External small undefined
Z [DIGITAL] No storage allocated
[DIGITAL] If the -a option is specified, an expanded listing in System V
format is written, formatted with the following columns:
Name
The symbol or external name
Value
Value field for the symbol or external, usually an address or
interesting debugging information
Class
The symbol type
Type
The symbol's declaration
Size
The symbol's size
Index
The symbol's index field
Section
The symbol's storage class
SEE ALSO
Functions: ar(1), c89(1)
Standards: standards(5)
Programmer's Guide, Assembly Language Programmer's Guide