CBMC vs Lean
CBMC
diffblue.github.io
Lean
lean-lang.orgSide by side
| Figure | CBMC | Lean |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | — | Yes |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 1 | 1 |
| Spec score · Formal Verification Tools | 8.1 (#8) | 8.6 (#2) |
| License | The repository identifies CBMC as licensed under the 4-clause BSD license. | Lean is released under the Apache 2.0 license, which the documentation describes as allowing others to use and extend the code and mathematical libraries freely. |
| Platforms | The installation guide points to installation instructions for macOS, Ubuntu, Windows, and Docker. | The reference lists Linux, macOS, and Windows among Lean’s supported platforms, with Tier 1 binary releases available through elan. |
| Support | The repository asks users encountering problems to file a bug report as a GitHub issue. | The Lean Community Zulip is described as the central hub for questions and collaboration, and Lean FRO hosts weekly technical office hours. |
Plans
In their own words
CBMC
CBMC is a bounded model checker for C and C++ programs. It explores execution paths to check assertions, including array bounds, pointer safety, exceptions, and some undefined behavior such as signed integer overflow. Its analysis unwinds loops before sending the resulting equation to a decision procedure, and inputs may need a bounded size. The repository lists C89, C99, most of C11, C17, C23, GCC and Visual Studio extensions, and SystemC through Scoot; the listed input languages also include Java bytecode. CBMC supports contracts and can produce counterexamples. Its incremental SMT2 backend works with SMT-LIB 2.6-compliant solvers, with Z3 and CVC5 as examples. Distribution options include Homebrew instructions for macOS, Ubuntu DEB packages, Windows MSI installers, and Docker images. goto-cc can replace gcc or cl.exe in Makefiles to collect project models. The guide discusses routine development and continuous integration use. CBMC is free under the 4-clause BSD license.
Lean
Lean is an open-source programming language and proof assistant for formalizing mathematics, verifying software, and writing general code. Its minimal trusted kernel checks proofs, and the project describes it as supporting correctness in mathematical, software, and hardware verification. Lean includes the Grind tool for automating some pattern matching, case analysis, and systems of linear inequalities; metaprogramming lets users add notation and proof automation. Projects are managed with Lake, the package manager bundled with Lean. Mathlib is a community-driven library with over a million lines spanning areas including algebra, analysis, topology, probability, and computer science. The recommended setup uses VS Code with the Lean 4 extension for syntax highlighting and code completion, while Neovim with lean.nvim is also well-supported. Lean runs on Linux, macOS, and Windows, and Lean4Web lets users run code in a browser. The software is free under the Apache 2.0 license. Learning resources include textbooks, tutorials, interactive games, documentation, and an API reference.