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Commands Reference, Volume 4
The nm command includes information for nm on a POWER-based platform and an nm on an Itanium-based platform.
nm Command on POWER-based
Platform
Displays information about
symbols in object files, executable files, and object-file libraries.
nm [ -A ] [ -C ] [ -X
{32|64|32_64}] [ -f ] [ -h ] [ -p ] [ -r
] [ -T ]
[ -v ] [ -B | -P
] [ -e | -g | -u ]
[ -d | -o
| -x | -t Format ] File
...
The nm command
displays information about symbols in the specified File, which can
be an object file, an executable file, or an object-file library. If
the file contains no symbol information, the nm command reports the
fact, but does not interpret it as an error condition. The
nm command reports numerical values in decimal notation by
default.
The nm command writes
the following symbol information to standard output:
- Library or
Object Name
The nm command reports
either the library or the object name associated with the file only if you
specify the -A option.
- Symbol Name
- Symbol Type
The nm command
represents the file's symbol type with one of the following
characters:
| A
| Global absolute symbol.
|
| a
| Local absolute symbol.
|
| B
| Global bss symbol.
|
| b
| Local bss symbol.
|
| D
| Global data symbol.
|
| d
| Local data symbol.
|
| f
| Source file name symbol.
|
| T
| Global text symbol.
|
| t
| Local text symbol.
|
| U
| Undefined symbol.
|
- Value
- Size
The nm command reports
the size associated with the symbol, if applicable.
| -A
| Displays either the full path name or library name of an object on each
line.
|
| -B
| Displays output in the Berkeley Software Distribution (BSD) format:
value type name
|
| -C
| Suppresses the demangling of C++ names. The default is to demangle
all C++ symbol names.
Note: Symbols from C++ object files have their names
demangled before they are used.
|
| -d
| Displays a symbol's value and size as a decimal. This is the
default.
|
| -e
| Displays only static and external (global) symbols.
|
| -f
| Displays full output, including redundant .text, .data, and
.bss symbols, which are normally suppressed.
|
| -g
| Displays only external (global) symbols.
|
| -h
| Suppresses the display of output header data.
|
| -o
| Displays a symbol's value and size as an octal rather than a decimal
number.
|
| -P
| Displays information in a standard portable output format:
library/object name name type value size
This format displays numerical
values in hexadecimal notation, unless you specify a different format with the
-t, -d, or -o flags.
The -P flag displays
the library/object name field only if you specify the -A
flag. Also, the -P flag displays the size field
only for symbols for which size is applicable.
|
| -p
| Does not sort. The Ouput is printed in symbol-table order.
|
| -r
| Sorts in reverse order.
|
| -T
| Truncates every name that would otherwise overflow its column, making the
last character displayed in the name an asterisk. By default,
nm displays the entire name of the symbols listed, and a name that
is longer than the width of the column set aside for it causes every column
after the name to be misaligned.
|
| -t Format
| Displays numerical values in the specified format, where the
Format parameter is one of the following notations:
- d
- Decimal notation. This is the default format for the nm
command.
- o
- Octal notation.
- x
- Hexadecimal notation.
|
| -u
| Displays only undefined symbols.
|
| -v
| Sorts output by value instead of alphabetically.
|
| -x
| Displays a symbol's value and size as a hexadecimal rather than a
decimal number.
|
| -X mode
| Specifies the type of object file nm should examine.
The mode must be one of the following:
- 32
- Processes only 32-bit object files
- 64
- Processes only 64-bit object files
- 32_64
- Processes both 32-bit and 64-bit object files
The default is to process 32-bit object files (ignore 64-bit
objects). The mode can also be set withe the
OBJECT_MODE environment variable. For example,
OBJECT_MODE=64 causes nm to process any 64-bit objects
and ignore 32-bit objects. The -X flag overrides the
OBJECT_MODE variable.
|
Note: The
nm command supports the -- (double hyphen)
flag. This flag distinguishes a File operand if the file
name can be misinterpreted as an option. For example, to specify a file
name that begins with a hyphen, use the -- flag:
This command returns the
following exit values:
| 0
| Successful completion.
|
| >0
| An error occurred.
|
- To list the static and external
symbols of the object file a.out, enter:
nm -e a.out
- To display symbol sizes and
values as hexadecimal and sort the symbols by value, enter:
nm -xv a.out
- To display symbol of all 64-bit objects in libc.a,
ignoring all 32-bit objects:
nm -X64 /usr/lib/libc.a
| /usr/ccs/bin/nm
| Contains the nm command.
|
The ar command, as
command, ld command, size command, strip command.
The a.out file, ar file.
Commands
Overview in AIX 5L Version 5.1 System User's Guide:
Operating System and Devices.
nm Command on Itanium-based
Platform
Print name list of an object file.
nm [ -goxhtnvsnurplCVAPR ] files
The nm command displays the symbol table of each ELF object
file, specified by file(s). The file may be a relocatable or
absolute ELF object file; or it may be an archive of relocatable or
absolute ELF object files. For each symbol, the following information
will be printed:
- Index
- The index of the symbol. (The index appears in brackets.)
- Value
- The value of the symbol is one of the following: a section offset
for defined symbols in a relocatable file; alignment constraints for
symbols whose section index is "SHN_COMMON"; a virtual address in
executable and dynamic library files.
- Size
- The size in bytes of the associated object.
- Type
- A symbol is of one of the following types: "NOTYPE" (no type
was specified), "OBJECT" (a data object such as an array or variable),
"FUNC" (a function or other executable code), "SECTION" (a section
symbol), or "FILE" (name of the source file).
- Bind
- The symbol's binding attributes. "LOCAL" symbols have a
scope limited to the object file containing their definition;
"GLOBAL" symbols are visible to all object files being combined; and
"WEAK" symbols are essentially global symbols with a lower precedence
than "GLOBAL".
- Other
- This field currently indicates the visibility of the symbol. 0
indicates default visibility. "HIDDEN" means the symbol is visible
solely within the object but not exported to other objects. "PROT"
means the symbol is "protected". Any reference to the symbol from
within the object will go to this definition, even if other definitions are
present and would normally take precedence.
- Shndx
- Except for three special values, this is the section header table index in
relation to which the symbol is defined. The following special values
exist: "ABS" indicates the symbol's value will not change
through relocation; "COMMON" indicates an unallocated block and the
value provides alignment constraints; and "UNDEF" indicates an
undefined symbol.
- Name
- The name of the symbol.
The output of nm may be controlled using the following
options:
- -g
- Only print symbols with binding types GLOBAL and WEAK.
- -o
- Print the value and size of a symbol in octal instead of decimal.
- -x
- Print the value and size of a symbol in hexadecimal instead of
decimal.
- -t d | o | x
- Set output format to decimal, octal or hexadecimal. (Decimal is the
default; -t o is equivalent to -o; -t
x is equivalent to -x)
- -h
- Do not display the output heading data.
- -v
- Sort external symbols by value before they are printed.
- -s
- Print section names instead of section indices.
- -n
- Sort external symbols by name before they are printed.
- -u
- Print undefined symbols only.
- -r
- Prepend the name of the object file or archive to each symbol name.
This option is ignored if -P is specified.
- -p [-l]
- Produce terse output that can be parsed easily. Each symbol name is
preceded by its value (blanks if undefined) and one of the letters "U"
(undefined symbol reference), "A" (absolute symbol) "B" (symbol
defined in .bss or a common symbol) "N" (symbol has no
type), "D" (data object symbol), "T" (text symbol), "S"
(section symbol), or "F" (file symbol). If the symbol's
binding attribute is "LOCAL", the key letter is lower case; if the
symbol's binding attribute is "WEAK", the key letter is upper case
(if the -l modifier is specified, the upper case key letter is
followed by an "*"); if the symbol's binding attribute is
"GLOBAL", the key letter is upper case.
- -C
- Print C++ names decoded.
- -V
- Print on the standard error output the version number of the nm
command being executed.
- -A
- Prepend the name of the object file and archive to each output
line.
- -P [-l]
- Alternate form of terse, easily parseable output (see
-p). The symbol name appears first, followed by a keyletter
(as described under -p), the symbol's value and its
size. The value and size fields are printed in hexadecimal, by
default.
- -R
- Prepend the name of the object file and archive to each symbol
name. This option is ignored if -P is specified.
Options may be used in any order, either singly or in combination, and may
appear anywhere in the command line. When conflicting options are
specified (such as nm -v -n) the first is taken and the second
ignored with a warning message to the user.
The a.out file format, ar file format.
The ar command, as command, cc command, dump command, and ld command.
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