Python C++ Symbol Demangler

0.3.0 · active · verified Sun Apr 12

Cxxfilt provides a Python interface to demangle C++ symbol names, typically found in compiled binaries or stack traces. It wraps the functionality of system utilities like `c++filt` or `abi::__cxa_demangle`. The current version is 0.3.0, and it is actively maintained on GitHub.

Warnings

breaking Python 2.7 is no longer supported in `cxxfilt` versions 0.3.0 and above. For Python 2.7 compatibility, use `cxxfilt` version < 0.3.
Fix: Upgrade to Python 3.6+ or pin `cxxfilt<0.3` for Python 2.7 projects.
gotcha The library does not officially support Windows environments. It is primarily tested on Linux and macOS, and is expected to work on Unix-like systems with `libc` and `libc++/libstdc++`.
Fix: Consider using alternative tools or a Linux/macOS environment for demangling C++ symbols on Windows. Contributions for Windows support are welcome.
gotcha Although `import cxxfilt` no longer fails if system C/C++ libraries are unavailable (since v0.3.0), attempting to demangle symbols will fail or raise `LibraryNotFound` or `InternalError` if the underlying native demangling functions are not accessible.
Fix: Ensure that `libc` and either `libc++` or `libstdc++` are installed on your system. You can programmatically check for demangler validity using `not isinstance(cxxfilt.default_demangler, cxxfilt.DeferedErrorDemangler)`.
gotcha The `cxxfilt.demangle()` function can raise an `InvalidName` exception if the provided string is not a valid C++ ABI mangled name.
Fix: Implement error handling (e.g., `try-except cxxfilt.InvalidName`) when demangling user-provided or untrusted symbol names.

Install

pip install cxxfilt Install stable release

Imports

demangle

import cxxfilt
symbol_name = '_ZNSt22condition_variable_anyD2Ev'
demangled_name = cxxfilt.demangle(symbol_name)

The primary function for demangling C++ symbols.

Quickstart

Demangle a common C++ mangled symbol and check the validity of the internal demangler.

import cxxfilt

mangled_symbol = '_ZNSt22condition_variable_anyD2Ev'
demangled_symbol = cxxfilt.demangle(mangled_symbol)
print(f"Mangled: {mangled_symbol}")
print(f"Demangled: {demangled_symbol}")

# To check if the underlying demangler is valid (e.g., if system libraries are present)
# The import itself no longer fails if libraries are missing since v0.3.0.
is_demangler_valid = not isinstance(cxxfilt.default_demangler, cxxfilt.DeferedErrorDemangler)
print(f"Is demangler valid: {is_demangler_valid}")

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