c++filt






c++filt − Demangle C++ and Java symbols.

c++filt [−_|−−strip−underscore]
        [−n|−−no−strip−underscore]
        [−p|−−no−params]
        [−t|−−types]
        [−i|−−no−verbose]
        [−s format|−−format=format]
        [−−help]  [−−version]  [symbol...]

The C++ and Java languages provide function overloading,
which means that you can write many functions with the same
name, providing that each function takes parameters of
different types.  In order to be able to distinguish these
similarly named functions C++ and Java encode them into a
low‐level assembler name which uniquely identifies each
different version.  This process is known as mangling. The
c++filt [1] program does the inverse mapping: it decodes
(demangles) low‐level names into user‐level names so that
they can be read.

     Every alphanumeric word (consisting of letters, digits,
underscores, dollars, or periods) seen in the input is a
potential mangled name.  If the name decodes into a C++
name, the C++ name replaces the low‐level name in the
output, otherwise the original word is output.  In this way
you can pass an entire assembler source file, containing
mangled names, through c++filt and see the same source file
containing demangled names.

     You can also use c++filt to decipher individual symbols
by passing them on the command line:

             c++filt <symbol>

     If no symbol arguments are given, c++filt reads symbol
names from the standard input instead.  All the results are
printed on the standard output.  The difference between
reading names from the command line versus reading names
from the standard input is that command line arguments are
expected to be just mangled names and no checking is
performed to separate them from surrounding text.  Thus for
example:

             c++filt −n _Z1fv

     will work and demangle the name to "f()" whereas:

             c++filt −n _Z1fv,

     will not work.  (Note the extra comma at the end of the
mangled name which makes it invalid).  This command however
will work:










                             ‐2‐


             echo _Z1fv, | c++filt −n

     and will display "f(),", i.e., the demangled name
followed by a trailing comma.  This behaviour is because
when the names are read from the standard input it is
expected that they might be part of an assembler source file
where there might be extra, extraneous characters trailing
after a mangled name.  For example:

                 .type   _Z1fv, @function



−_

−−strip−underscore
    On some systems, both the C and C++ compilers put an
    underscore in front of every name.  For example, the C
    name "foo" gets the low‐level name "_foo".  This option
    removes the initial underscore.  Whether c++filt removes
    the underscore by default is target dependent.

−n

−−no−strip−underscore
    Do not remove the initial underscore.

−p

−−no−params
    When demangling the name of a function, do not display
    the types of the function’s parameters.

−t

−−types
    Attempt to demangle types as well as function names.
    This is disabled by default since mangled types are
    normally only used internally in the compiler, and they
    can be confused with non‐mangled names.  For example, a
    function called "a" treated as a mangled type name would
    be demangled to "signed char".

−i

−−no−verbose
    Do not include implementation details (if any) in the
    demangled output.

−s format

−−format=format
    c++filt can decode various methods of mangling, used by
    different compilers.  The argument to this option









                             ‐3‐


    selects which method it uses:

    "auto"
        Automatic selection based on executable (the default
        method)

    "gnu"
        the one used by the GNU C++ compiler (g++)

    "lucid"
        the one used by the Lucid compiler (lcc)

    "arm"
        the one specified by the C++ Annotated Reference
        Manual

    "hp"
        the one used by the HP compiler (aCC)

    "edg"
        the one used by the EDG compiler

    "gnu−v3"
        the one used by the GNU C++ compiler (g++) with the
        V3 ABI.

    "java"
        the one used by the GNU Java compiler (gcj)

    "gnat"
        the one used by the GNU Ada compiler (GNAT).

−−help
    Print a summary of the options to c++filt and exit.

−−version
    Print the version number of c++filt and exit.

@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.











                             ‐4‐




1.  MS‐DOS does not allow "+" characters in file names, so
    on MS‐DOS this program is named CXXFILT.

the Info entries for binutils.

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