Originální popis anglicky:
nm - write the name list of an object file (
DEVELOPMENT)
Návod, kniha: POSIX Programmer's Manual
nm [-APv][-efox][ -g|
-u][ -t format] file...
This utility shall be provided on systems that support both the User Portability
Utilities option and the Software Development Utilities option. On other
systems it is optional. Certain options are only available on XSI-conformant
systems.
The
nm utility shall display symbolic information appearing in the object
file, executable file, or object-file library named by
file. If no
symbolic information is available for a valid input file, the
nm
utility shall report that fact, but not consider it an error condition.
The default base used when numeric values are written is unspecified. On
XSI-conformant systems, it shall be decimal.
The
nm utility shall conform to the Base Definitions volume of
IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
- -A
- Write the full pathname or library name of an object on
each line.
- -e
- Write only external (global) and static symbol
information.
- -f
- Produce full output. Write redundant symbols (
.text, .data, and .bss), normally suppressed.
- -g
- Write only external (global) symbol information.
- -o
- Write numeric values in octal (equivalent to
-t o).
- -P
- Write information in a portable output format, as specified
in the STDOUT section.
- -t format
- Write each numeric value in the specified format. The
format shall be dependent on the single character used as the
format option-argument:
- d
The offset is written in decimal
(default).
- o
The offset is written in octal.
- x
The offset is written in hexadecimal.
- -u
- Write only undefined symbols.
- -v
- Sort output by value instead of alphabetically.
- -x
- Write numeric values in hexadecimal (equivalent to
-t x).
The following operand shall be supported:
- file
- A pathname of an object file, executable file, or
object-file library.
See the INPUT FILES section.
The input file shall be an object file, an object-file library whose format is
the same as those produced by the
ar utility for link editing, or an
executable file. The
nm utility may accept additional
implementation-defined object library formats for the input file.
The following environment variables shall affect the execution of
nm:
- LANG
- Provide a default value for the internationalization
variables that are unset or null. (See the Base Definitions volume of
IEEE Std 1003.1-2001, Section 8.2, Internationalization
Variables for the precedence of internationalization variables used to
determine the values of locale categories.)
- LC_ALL
- If set to a non-empty string value, override the values of
all the other internationalization variables.
- LC_COLLATE
-
Determine the locale for character collation information for the symbol-name
and symbol-value collation sequences.
- LC_CTYPE
- Determine the locale for the interpretation of sequences of
bytes of text data as characters (for example, single-byte as opposed to
multi-byte characters in arguments).
- LC_MESSAGES
- Determine the locale that should be used to affect the
format and contents of diagnostic messages written to standard error.
- NLSPATH
- Determine the location of message catalogs for the
processing of LC_MESSAGES .
Default.
If symbolic information is present in the input files, then for each file or for
each member of an archive, the
nm utility shall write the following
information to standard output. By default, the format is unspecified, but the
output shall be sorted alphabetically by symbol name:
- *
- Library or object name, if -A is specified
- *
- Symbol name
- *
- Symbol type, which shall either be one of the following
single characters or an implementation-defined type represented by a
single character:
- A
Global absolute symbol.
- a
Local absolute symbol.
- B
Global "bss" (that is, uninitialized
data space) symbol.
- b
Local bss symbol.
- D
Global data symbol.
- d
Local data symbol.
- T
Global text symbol.
- t
Local text symbol.
- U
Undefined symbol.
- *
- Value of the symbol
- *
- The size associated with the symbol, if applicable
This information may be supplemented by additional information specific to the
implementation.
If the
-P option is specified, the previous information shall be
displayed using the following portable format. The three versions differ
depending on whether
-t d,
-t o, or
-t x was specified, respectively:
"%s%s %s %d %d\n", <library/object name>, <name>, <type>,
<value>, <size>
"%s%s %s %o %o\n", < library/object name>, <name>, <type>,
<value>, <size>
"%s%s %s %x %x\n", < library/object name>, <name>, <type>,
<value>, <size>
where <library/object name> shall be formatted as
follows:
- *
- If -A is not specified,
<library/object name> shall be an empty string.
- *
- If -A is specified and the corresponding file
operand does not name a library:
- *
- If -A is specified and the corresponding file
operand names a library. In this case, < object file>
shall name the object file in the library containing the symbol being
described:
"%s[%s]: ", <file>, <object file>
If
-A is not specified, then if more than one
file operand is
specified or if only one
file operand is specified and it names a
library,
nm shall write a line identifying the object containing the
following symbols before the lines containing those symbols, in the form:
- *
- If the corresponding file operand does not name a
library:
- *
- If the corresponding file operand names a library;
in this case, < object file> shall be the name of the
file in the library containing the following symbols:
"%s[%s]:\n", <file>, <object file>
If
-P is specified, but
-t is not, the format shall be as if
-t x had been specified.
The standard error shall be used only for diagnostic messages.
None.
None.
The following exit values shall be returned:
- 0
- Successful completion.
- >0
- An error occurred.
Default.
The following sections are informative.
Mechanisms for dynamic linking make this utility less meaningful when applied to
an executable file because a dynamically linked executable may omit numerous
library routines that would be found in a statically linked executable.
None.
Historical implementations of
nm have used different bases for numeric
output and supplied different default types of symbols that were reported. The
-t format option, similar to that used in
od and
strings, can be used to specify the numeric base;
-g and
-u can be used to restrict the amount of output or the types of symbols
included in the output.
The compromise of using
-t format versus using
-d,
-o, and other similar options was necessary because of differences in
the meaning of
-o between implementations. The
-o option from
BSD has been provided here as
-A to avoid confusion with the
-o
from System V (which has been provided here as
-t and as
-o on
XSI-conformant systems).
The option list was significantly reduced from that provided by historical
implementations.
The
nm description is a subset of both the System V and BSD
nm
utilities with no specified default output.
It was recognized that mechanisms for dynamic linking make this utility less
meaningful when applied to an executable file (because a dynamically linked
executable file may omit numerous library routines that would be found in a
statically linked executable file), but the value of
nm during software
development was judged to outweigh other limitations.
The default output format of
nm is not specified because of differences
in historical implementations. The
-P option was added to allow some
type of portable output format. After a comparison of the different formats
used in SunOS, BSD, SVR3, and SVR4, it was decided to create one that did not
match the current format of any of these four systems. The format devised is
easy to parse by humans, easy to parse in shell scripts, and does not need to
vary depending on locale (because no English descriptions are included). All
of the systems currently have the information available to use this format.
The format given in
nm STDOUT uses spaces between the fields, which may
be any number of <blank>s required to align the columns. The
single-character types were selected to match historical practice, and the
requirement that implementation additions also be single characters made
parsing the information easier for shell scripts.
None.
ar ,
c99
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
