Boost.Stacktrace is a production-grade C++ library for capturing, storing, and printing backtraces (call stacks). It provides a header-only core with optional compiled backends that leverage platform-specific mechanisms: `_Unwind_Backtrace` (POSIX), `backtrace()` (glibc), `libbacktrace`, `addr2line`, or Windows Debug Engine (`dbgeng`). The library offers signal-safe raw dump functions, human-readable frame decoding (function names, source file, line number), and the ability to capture stacktraces at the point an exception is thrown via `from_current_exception()`. The design is modular, with separate compiled libraries for each backend and a no-op backend to disable tracing. The codebase is well-structured, heavily tested across compilers and platforms, and actively maintained. It demonstrates deep knowledge of C++ runtime internals, particularly in the exception interception implementation that hooks into `__cxa_allocate_exception` or uses vectored exception handlers on Windows. While the library itself is the reusable asset, several internal utilities (e.g., address base computation from `/proc/self/maps`, `dladdr` abstraction) embody patterns useful in other debugging and profiling tools.
SNAFU is a Rust library for ergonomic error handling. It provides a `#[derive(Snafu)]` proc-macro that generates custom error types with automatic 'context selectors' (e.g., `ReadConfigSnafu`) and implements standard traits (`Display`, `Error`, `From`). The library also offers extension traits (`ResultExt`, `OptionExt`, `TryFutureExt`, `TryStreamExt`) to attach contextual information to underlying errors, macros (`ensure!`, `whatever!`) for concise error creation, and a `Report` type for user-facing error output. It supports `no_std` environments (with `alloc`) and includes backtrace capture, location tracking, and an unstable provider API for attaching arbitrary data to errors. The crate is mature and widely adopted, but contains some deprecated features (e.g., `backtraces-impl-backtrace-crate`) and a complex feature-flag matrix. The companion `snafu-derive` crate handles all proc-macro generation, and the architecture cleanly separates parsing, validation, and code generation.