c++filt(1): Demangle C++/Java symbols – Linux man page

Name

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

Synopsis

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

Description

The C ++ and Java languages provide function overloading, which means that you can write many functions with the same name, providing thateach function takes parameters of different types. In order to be able to distinguish these similarly named functions C ++ and Java encode theminto a low-level assembler name which uniquely identifies each different version. This process is known as mangling. The c++filt [1] program doesthe 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 decodesinto a C ++ name, the C ++ name replaces the low-level name in the output, otherwise the original word is output. In this way youcan 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 standardoutput. The difference between reading names from the command line versus reading names from the standard input is that command line arguments are expected tobe 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:

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 itis 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

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