1.\" Copyright (c) 2007 Hyogeol Lee <hyogeollee@gmail.com> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer 9.\" in this position and unchanged. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 15.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24.\" 25.\" $Id: nm.1 3573 2017-09-14 02:06:31Z emaste $ 26.\" 27.Dd September 13, 2017 28.Os 29.Dt NM 1 30.Sh NAME 31.Nm nm 32.Nd display symbolic information in object files 33.Sh SYNOPSIS 34.Nm 35.Op Fl -debug-syms 36.Op Fl -defined-only 37.Op Fl -demangle Ns Op = Ns style 38.Op Fl -dynamic 39.Op Fl -extern-only 40.Op Fl -help 41.Op Fl -line-numbers 42.Op Fl -no-demangle 43.Op Fl -no-sort 44.Op Fl -numeric-sort 45.Op Fl -print-armap 46.Op Fl -print-file-name 47.Op Fl -print-size 48.Op Fl -radix= Ns Ar format 49.Op Fl -reverse-sort 50.Op Fl -size-sort 51.Op Fl -undefined-only 52.Op Fl -version 53.Op Fl A 54.Op Fl B 55.Op Fl C Op Ar style 56.Op Fl D 57.Op Fl P 58.Op Fl V 59.Op Fl a 60.Op Fl e 61.Op Fl g 62.Op Fl h 63.Op Fl l 64.Op Fl n 65.Op Fl o 66.Op Fl p 67.Op Fl r 68.Op Fl S 69.Op Fl s 70.Op Fl t Ar format 71.Op Fl u 72.Op Fl x 73.Ar 74.Sh DESCRIPTION 75The 76.Nm 77utility displays symbolic information in the object files, 78executables, and object library files named by its arguments. 79Lack of symbolic information in an otherwise valid input 80file, is not considered to be an error. 81If no files are specified on the command line, 82.Nm 83will attempt to read 84.Pa a.out . 85.Pp 86The 87.Nm 88utility recognizes the following options: 89.Bl -tag -width ".Fl d Ar argument" 90.It Fl -debug-syms 91Display all symbols, including debugger-only symbols. 92.It Fl -defined-only 93Display only defined symbols. 94.It Fl -demangle Ns Op = Ns Ar style 95Decode (demangle) low-level symbol names into human-readable names. 96Supported values for argument 97.Ar style 98are 99.Sq auto , 100.Sq gnu-v2 , 101.Sq gnu-v3 102and 103.Sq arm. 104If argument 105.Ar style 106is not specified, it is taken to be 107.Sq auto . 108.It Fl -dynamic 109Only display dynamic symbols. 110This option is only meaningful for shared libraries. 111.It Fl -extern-only 112Only display information about global (external) symbols. 113.It Fl -help 114Display a help message and exit. 115.It Fl -format Ns = Ns Ar format 116Display output in the format specified by argument 117.Ar format . 118Supported values for the format argument are 119.Sq bsd , 120.Sq sysv , 121and 122.Sq posix . 123The default output format is 124.Sq bsd . 125.It Fl -line-numbers 126Display the filename and line number associated a symbol using 127any debugging information present in the input file. 128For defined symbols, look up the line number associated with 129the address of the symbol. 130For undefined symbols, look up the line number associated with 131a relocation entry that refers to the symbol. 132If line number information can be determined, it is displayed after 133other symbol information. 134.It Fl -no-demangle 135Do not demangle symbol names (default). 136.It Fl -no-sort 137Do not sort symbols. 138.It Fl -numeric-sort 139Sort symbols numerically by address instead of alphabetically by name. 140.It Fl -print-armap 141For 142.Xr ar 1 143archives, include the index of the archive's members. 144.It Fl -print-file-name 145Write the full pathname or library name of an object on each line, 146before the rest of the information for a symbol. 147If this option is not specified, 148.Nm 149will only identify an input file once, before its symbols are 150listed. 151.It Fl -print-size 152Print the size of each symbol instead of its value. 153.It Fl -radix Ns = Ns Ar radix 154Print numeric values using the specified radix. 155Supported values for argument 156.Ar radix 157are 158.Sq d 159for decimal, 160.Sq o 161for octal, and 162.Sq x 163for hexadecimal. 164.It Fl -reverse-sort 165Reverse the order of the sort. 166.It Fl -size-sort 167Sort symbols by size instead of alphabetically by name. 168.It Fl -undefined-only 169Display only undefined symbols. 170.It Fl -version 171Display the version identifier for 172.Nm 173and exit. 174.It Fl A 175Equivalent to specifying option 176.Fl -print-file-name . 177.It Fl B 178Equivalent to specifying option 179.Fl -format= Ns Ar bsd . 180.It Fl C Op Ar style 181Equivalent to specifying option 182.Fl -demangle Ns Op = Ns Ar style . 183.It Fl D 184Equivalent to specifying option 185.Fl -dynamic . 186.It Fl F Ar format 187Equivalent to specifying option 188.Fl -format Ns = Ns Ar format . 189.It Fl P 190Equivalent to specifying option 191.Fl -format Ns = Ns Ar posix . 192.It Fl S 193Equivalent to specifying option 194.Fl -print-size . 195.It Fl V 196Equivalent to specifying option 197.Fl -version . 198.It Fl a 199Equivalent to specifying option 200.Fl -debug-syms . 201.It Fl e 202Only display information for global and static symbols. 203.It Fl f 204Produce full output (default). 205.It Fl g 206Equivalent to specifying option 207.Fl -extern-only . 208.It Fl h 209Equivalent to specifying option 210.Fl -help . 211.It Fl l 212Equivalent to specifying option 213.Fl -line-numbers . 214.It Fl n 215Equivalent to specifying option 216.Fl -numeric-sort . 217.It Fl o 218If POSIX output was specified using the 219.Fl F Ar posix 220or 221.Fl P 222options, this option is equivalent to specifying 223.Fl -radix Ns = Ns Sq Ar o . 224If POSIX output was not specified, this option 225acts as a synonym for the 226.Fl -print-file-name 227option. 228.It Fl p 229Equivalent to specifying option 230.Fl -no-sort . 231.It Fl v 232Equivalent to option 233.Fl n . 234.It Fl r 235Equivalent to specifying option 236.Fl -reverse-sort 237.It Fl s 238Equivalent to specifying option 239.Fl -print-armap . 240.It Fl t Ar radix 241Equivalent to specifying option 242.Fl -radix= Ns Ar radix . 243.It Fl u 244Equivalent to specifying option 245.Fl -undefined-only . 246.It Fl x 247Write numeric values in hexadecimal (equivalent to -t x). 248.El 249.Sh OUTPUT FORMAT 250.Pp 251The 252.Nm 253utility can present its information in a number of formats, numeric 254radices and sort orders. 255By default 256.Nm 257uses BSD style output, a hexadecimal radix, without output sorted 258alphabetically by name and without demangling of names. 259.Pp 260For each symbol listed, 261.Nm 262presents the following information: 263.Bl -bullet -compact 264.It 265The library or object name, if options 266.Fl A 267or 268.Fl -print-file-name 269were specified. 270.It 271The symbol name. 272.It 273The type of the symbol denoted by a single character as below: 274.Bl -tag -compact -width indent 275.It A 276A global, absolute symbol. 277.It B 278A global 279.Dq bss 280(uninitialized data) symbol. 281.It C 282A 283.Dq common 284symbol, representing uninitialized data. 285.It D 286A global symbol naming initialized data. 287.It N 288A debugger symbol. 289.It R 290A read-only data symbol. 291.It T 292A global text symbol. 293.It U 294An undefined symbol. 295.It V 296A weak object. 297.It W 298A weak reference. 299.It a 300A local absolute symbol. 301.It b 302A local 303.Dq bss 304(uninitialized data) symbol. 305.It d 306A local data symbol. 307.It r 308A local read-only data symbol. 309.It t 310A local text symbol. 311.It v 312A weak object that is undefined. 313.It w 314A weak symbol that is undefined. 315.It ? 316None of the above. 317.El 318.It 319The value of the symbol. 320.It 321The size of the symbol if applicable. 322.It 323Line number information, if available and if options 324.Fl l 325or 326.Fl -line-numbers 327were specified. 328.El 329.Sh EXIT STATUS 330.Ex -std 331.Sh SEE ALSO 332.Xr ar 1 , 333.Xr objdump 1 , 334.Xr ranlib 1 , 335.Xr elf 3 336.Sh AUTHORS 337The 338.Nm 339utility and this manual page were written by 340.An Hyogeol Lee Aq Mt hyogeollee@gmail.com . 341