# nm

## NAME



           nm - list symbols from object files
    


## SYNOPSIS



           nm [**-A** |**-o** |**--print-file-name**]
              [**-a** |**--debug-syms**]
              [**-B** |**--format=bsd**]
              [**-C** |**--demangle**[=_style_]]
              [**-D** |**--dynamic**]
              [**-f** _format_ |**--format=**_format_]
              [**-g** |**--extern-only**]
              [**-h** |**--help**]
              [**--ifunc-chars=**_CHARS_]
              [**-j** |**--format=just-symbols**]
              [**-l** |**--line-numbers**] [**--inlines**]
              [**-n** |**-v** |**--numeric-sort**]
              [**-P** |**--portability**]
              [**-p** |**--no-sort**]
              [**-r** |**--reverse-sort**]
              [**-S** |**--print-size**]
              [**-s** |**--print-armap**]
              [**-t** _radix_ |**--radix=**_radix_]
              [**-u** |**--undefined-only**]
              [**-U** |**--defined-only**]
              [**-V** |**--version**]
              [**-W** |**--no-weak**]
              [**-X 32_64**]
              [**--no-demangle**]
              [**--no-recurse-limit** |**--recurse-limit**]]
              [**--plugin** _name_]
              [**--size-sort**]
              [**--special-syms**]
              [**--synthetic**]
              [**--target=**_bfdname_]
              [**--unicode=**_method_]
              [**--with-symbol-versions**]
              [**--without-symbol-versions**]
              [_objfile_...]
    


## DESCRIPTION



           GNU **nm** lists the symbols from object files _objfile_....  If no
           object files are listed as arguments, **nm** assumes the file _a.out_.
    
           For each symbol, **nm** shows:
    
           •   The symbol value, in the radix selected by options (see
               below), or hexadecimal by default.
    
           •   The symbol type.  At least the following types are used;
               others are, as well, depending on the object file format.  If
               lowercase, the symbol is usually local; if uppercase, the
               symbol is global (external).  There are however a few
               lowercase symbols that are shown for special global symbols
               ("u", "v" and "w").
    
               "A" The symbol's value is absolute, and will not be changed by
                   further linking.
    
               "B"
               "b" The symbol is in the BSS data section.  This section
                   typically contains zero-initialized or uninitialized data,
                   although the exact behavior is system dependent.
    
               "C"
               "c" The symbol is common.  Common symbols are uninitialized
                   data.  When linking, multiple common symbols may appear
                   with the same name.  If the symbol is defined anywhere,
                   the common symbols are treated as undefined references.
                   The lower case _c_ character is used when the symbol is in a
                   special section for small commons.
    
               "D"
               "d" The symbol is in the initialized data section.
    
               "G"
               "g" The symbol is in an initialized data section for small
                   objects.  Some object file formats permit more efficient
                   access to small data objects, such as a global int
                   variable as opposed to a large global array.
    
               "i" For PE format files this indicates that the symbol is in a
                   section specific to the implementation of DLLs.
    
                   For ELF format files this indicates that the symbol is an
                   indirect function.  This is a GNU extension to the
                   standard set of ELF symbol types.  It indicates a symbol
                   which if referenced by a relocation does not evaluate to
                   its address, but instead must be invoked at runtime.  The
                   runtime execution will then return the value to be used in
                   the relocation.
    
                   Note - the actual symbols display for GNU indirect symbols
                   is controlled by the **--ifunc-chars** command line option.
                   If this option has been provided then the first character
                   in the string will be used for global indirect function
                   symbols.  If the string contains a second character then
                   that will be used for local indirect function symbols.
    
               "I" The symbol is an indirect reference to another symbol.
    
               "N" The symbol is a debugging symbol.
    
               "n" The symbol is in a non-data, non-code, non-debug read-only
                   section.
    
               "p" The symbol is in a stack unwind section.
    
               "R"
               "r" The symbol is in a read only data section.
    
               "S"
               "s" The symbol is in an uninitialized or zero-initialized data
                   section for small objects.
    
               "T"
               "t" The symbol is in the text (code) section.
    
               "U" The symbol is undefined.
    
               "u" The symbol is a unique global symbol.  This is a GNU
                   extension to the standard set of ELF symbol bindings.  For
                   such a symbol the dynamic linker will make sure that in
                   the entire process there is just one symbol with this name
                   and type in use.
    
               "V"
               "v" The symbol is a weak object.  When a weak defined symbol
                   is linked with a normal defined symbol, the normal defined
                   symbol is used with no error.  When a weak undefined
                   symbol is linked and the symbol is not defined, the value
                   of the weak symbol becomes zero with no error.  On some
                   systems, uppercase indicates that a default value has been
                   specified.
    
               "W"
               "w" The symbol is a weak symbol that has not been specifically
                   tagged as a weak object symbol.  When a weak defined
                   symbol is linked with a normal defined symbol, the normal
                   defined symbol is used with no error.  When a weak
                   undefined symbol is linked and the symbol is not defined,
                   the value of the symbol is determined in a system-specific
                   manner without error.  On some systems, uppercase
                   indicates that a default value has been specified.
    
               "-" The symbol is a stabs symbol in an a.out object file.  In
                   this case, the next values printed are the stabs other
                   field, the stabs desc field, and the stab type.  Stabs
                   symbols are used to hold debugging information.
    
               "?" The symbol type is unknown, or object file format
                   specific.
    
           •   The symbol name.  If a symbol has version information
               associated with it, then the version information is displayed
               as well.  If the versioned symbol is undefined or hidden from
               linker, the version string is displayed as a suffix to the
               symbol name, preceded by an @ character.  For example
               **foo@VER_1**.  If the version is the default version to be used
               when resolving unversioned references to the symbol, then it
               is displayed as a suffix preceded by two @ characters.  For
               example **foo@@VER_2**.
    


## OPTIONS



           The long and short forms of options, shown here as alternatives,
           are equivalent.
    
           **-A**
           **-o**
           **--print-file-name**
               Precede each symbol by the name of the input file (or archive
               member) in which it was found, rather than identifying the
               input file once only, before all of its symbols.
    
           **-a**
           **--debug-syms**
               Display all symbols, even debugger-only symbols; normally
               these are not listed.
    
           **-B** The same as **--format=bsd**(for compatibility with the MIPS **nm**).
    
           **-C**
           **--demangle[=**_style_**]**
               Decode (_demangle_) low-level symbol names into user-level
               names.  Besides removing any initial underscore prepended by
               the system, this makes C++ function names readable. Different
               compilers have different mangling styles. The optional
               demangling style argument can be used to choose an appropriate
               demangling style for your compiler.
    
           **--no-demangle**
               Do not demangle low-level symbol names.  This is the default.
    
           **--recurse-limit**
           **--no-recurse-limit**
           **--recursion-limit**
           **--no-recursion-limit**
               Enables or disables a limit on the amount of recursion
               performed whilst demangling strings.  Since the name mangling
               formats allow for an infinite level of recursion it is
               possible to create strings whose decoding will exhaust the
               amount of stack space available on the host machine,
               triggering a memory fault.  The limit tries to prevent this
               from happening by restricting recursion to 2048 levels of
               nesting.
    
               The default is for this limit to be enabled, but disabling it
               may be necessary in order to demangle truly complicated names.
               Note however that if the recursion limit is disabled then
               stack exhaustion is possible and any bug reports about such an
               event will be rejected.
    
           **-D**
           **--dynamic**
               Display the dynamic symbols rather than the normal symbols.
               This is only meaningful for dynamic objects, such as certain
               types of shared libraries.
    
           **-f** _format_
           **--format=**_format_
               Use the output format _format_ , which can be "bsd", "sysv",
               "posix" or "just-symbols".  The default is "bsd".  Only the
               first character of _format_ is significant; it can be either
               upper or lower case.
    
           **-g**
           **--extern-only**
               Display only external symbols.
    
           **-h**
           **--help**
               Show a summary of the options to **nm** and exit.
    
           **--ifunc-chars=**_CHARS_
               When display GNU indirect function symbols **nm** will default to
               using the "i" character for both local indirect functions and
               global indirect functions.  The **--ifunc-chars** option allows
               the user to specify a string containing one or two characters.
               The first character will be used for global indirect function
               symbols and the second character, if present, will be used for
               local indirect function symbols.
    
           **j** The same as **--format=just-symbols**.
    
           **-l**
           **--line-numbers**
               For each symbol, use debugging information to try to find a
               filename and line number.  For a defined symbol, look for the
               line number of the address of the symbol.  For an undefined
               symbol, look for the line number of a relocation entry which
               refers to the symbol.  If line number information can be
               found, print it after the other symbol information.
    
           **--inlines**
               When option **-l** is active, if the address belongs to a function
               that was inlined, then this option causes the source
               information for all enclosing scopes back to the first
               non-inlined function to be printed as well.  For example, if
               "main" inlines "callee1" which inlines "callee2", and address
               is from "callee2", the source information for "callee1" and
               "main" will also be printed.
    
           **-n**
           **-v**
           **--numeric-sort**
               Sort symbols numerically by their addresses, rather than
               alphabetically by their names.
    
           **-p**
           **--no-sort**
               Do not bother to sort the symbols in any order; print them in
               the order encountered.
    
           **-P**
           **--portability**
               Use the POSIX.2 standard output format instead of the default
               format.  Equivalent to **-f posix**.
    
           **-r**
           **--reverse-sort**
               Reverse the order of the sort (whether numeric or alphabetic);
               let the last come first.
    
           **-S**
           **--print-size**
               Print both value and size of defined symbols for the "bsd"
               output style.  This option has no effect for object formats
               that do not record symbol sizes, unless **--size-sort** is also
               used in which case a calculated size is displayed.
    
           **-s**
           **--print-armap**
               When listing symbols from archive members, include the index:
               a mapping (stored in the archive by **ar** or **ranlib**) of which
               modules contain definitions for which names.
    
           **-t** _radix_
           **--radix=**_radix_
               Use _radix_ as the radix for printing the symbol values.  It
               must be **d** for decimal, **o** for octal, or **x** for hexadecimal.
    
           **-u**
           **--undefined-only**
               Display only undefined symbols (those external to each object
               file).  By default both defined and undefined symbols are
               displayed.
    
           **-U**
           **--defined-only**
               Display only defined symbols for each object file.  By default
               both defined and undefined symbols are displayed.
    
           **-V**
           **--version**
               Show the version number of **nm** and exit.
    
           **-X** This option is ignored for compatibility with the AIX version
               of **nm**.  It takes one parameter which must be the string **32_64**.
               The default mode of AIX **nm** corresponds to **-X 32** , which is not
               supported by GNU **nm**.
    
           **--plugin** _name_
               Load the plugin called _name_ to add support for extra target
               types.  This option is only available if the toolchain has
               been built with plugin support enabled.
    
               If **--plugin** is not provided, but plugin support has been
               enabled then **nm** iterates over the files in
               _${libdir}/bfd-plugins_ in alphabetic order and the first plugin
               that claims the object in question is used.
    
               Please note that this plugin search directory is _not_ the one
               used by **ld** 's **-plugin** option.  In order to make **nm** use the
               linker plugin it must be copied into the _${libdir}/bfd-plugins_
               directory.  For GCC based compilations the linker plugin is
               called _liblto_plugin.so.0.0.0_.  For Clang based compilations
               it is called _LLVMgold.so_.  The GCC plugin is always backwards
               compatible with earlier versions, so it is sufficient to just
               copy the newest one.
    
           **--size-sort**
               Sort symbols by size.  For ELF objects symbol sizes are read
               from the ELF, for other object types the symbol sizes are
               computed as the difference between the value of the symbol and
               the value of the symbol with the next higher value.  If the
               "bsd" output format is used the size of the symbol is printed,
               rather than the value, and **-S** must be used in order both size
               and value to be printed.
    
               Note - this option does not work if **--undefined-only** has been
               enabled as undefined symbols have no size.
    
           **--special-syms**
               Display symbols which have a target-specific special meaning.
               These symbols are usually used by the target for some special
               processing and are not normally helpful when included in the
               normal symbol lists.  For example for ARM targets this option
               would skip the mapping symbols used to mark transitions
               between ARM code, THUMB code and data.
    
           **--synthetic**
               Include synthetic symbols in the output.  These are special
               symbols created by the linker for various purposes.  They are
               not shown by default since they are not part of the binary's
               original source code.
    
           **--unicode=**_[default|invalid|locale|escape|hex|highlight]_
               Controls the display of UTF-8 encoded multibyte characters in
               strings.  The default (**--unicode=default**) is to give them no
               special treatment.  The **--unicode=locale** option displays the
               sequence in the current locale, which may or may not support
               them.  The options **--unicode=hex** and **--unicode=invalid** display
               them as hex byte sequences enclosed by either angle brackets
               or curly braces.
    
               The **--unicode=escape** option displays them as escape sequences
               (_\uxxxx_) and the **--unicode=highlight** option displays them as
               escape sequences highlighted in red (if supported by the
               output device).  The colouring is intended to draw attention
               to the presence of unicode sequences where they might not be
               expected.
    
           **-W**
           **--no-weak**
               Do not display weak symbols.
    
           **--with-symbol-versions**
           **--without-symbol-versions**
               Enables or disables the display of symbol version information.
               The version string is displayed as a suffix to the symbol
               name, preceded by an @ character.  For example **foo@VER_1**.  If
               the version is the default version to be used when resolving
               unversioned references to the symbol then it is displayed as a
               suffix preceded by two @ characters.  For example **foo@@VER_2**.
               By default, symbol version information is displayed.
    
           **--target=**_bfdname_
               Specify an object code format other than your system's default
               format.
    
           **@**_file_
               Read command-line options from _file_.  The options read are
               inserted in place of the original @_file_ option.  If _file_ does
               not exist, or cannot be read, then the option will be treated
               literally, and not removed.
    
               Options in _file_ are separated by whitespace.  A whitespace
               character may be included in an option by surrounding the
               entire option in either single or double quotes.  Any
               character (including a backslash) may be included by prefixing
               the character to be included with a backslash.  The _file_ may
               itself contain additional @_file_ options; any such options will
               be processed recursively.
    


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