CBMC

CBMC is a bounded model checker for C and C++ that checks program properties and can generate tests. It is best suited to developers who need targeted verification and are comfortable working from a command line. Its free, broad C/C++ support is appealing, but loop unwinding and the command-line-only workflow make it a specialist choice.

Overview

CBMC unwinds program loops and sends the resulting equation to a decision procedure. It checks memory safety, including array bounds and safe pointer use, along with several forms of undefined behavior and user-written assertions. This is useful when a team wants to verify specific properties over bounded behavior; it should not be mistaken for a guarantee across unbounded execution.

It can also check I/O equivalence between C or C++ and languages such as Verilog, which gives it a role in software-hardware interface work. That focus is narrower than a general code-review environment, and Windows and macOS users must work without a graphical interface.

Key features

• C and C++ coverage: CBMC supports C89, C99, most of C11 and C17, and many compiler extensions from GCC, Clang and Visual Studio. Supported features include multidimensional and dynamically sized arrays, pointers, dynamic memory, nondeterminism, assumptions and assertions. C++ support includes classes, templates and selected STL containers. This range makes it relevant to varied codebases, though support for only most of newer C standards and selected containers is a qualification worth checking against a project’s needs.
• Property checking: Memory checks, undefined-behavior checks and user assertions let developers focus analysis on concrete defect classes and requirements. The bounded loop-unwinding method is a meaningful constraint: its results depend on the analyzed bound rather than covering arbitrary execution.
• Test generation: CBMC can generate test cases for branch, decision, path and MC/DC coverage. That makes it useful when coverage-oriented tests are part of the goal as well as verification.
• Solver choices: A MiniSat-based bit-vector solver is included, so a separate solver is not required for that route. Boolector, CVC5 and Z3 are supported as external SMT solvers, but users must install them separately.
• Command-line operation: Windows provides an x64 command-line binary run from the Visual Studio Command Prompt; macOS is also command-line only. This suits scripted or terminal-based work, but readers seeking a graphical workflow should look elsewhere.

Pricing

CBMC is free: the CBMC plan costs nothing and is released under a BSD 4-clause license. There is no paid tier or free-trial decision to weigh. The license provides the software “AS IS” and disclaims warranties and liability, so organizations should account for those terms when adopting it.

Platforms

CBMC supports Linux, macOS and Windows. On Linux it is packaged for Debian and Ubuntu and can also be installed with Fedora’s dnf package manager. Windows and macOS distributions have no GUI, and the Windows binary is specifically x64 and launched from the Visual Studio Command Prompt. The tool’s platform reach is broad, but its interface expectations are not.

Who it's for

CBMC fits C and C++ developers who need to check memory safety, selected undefined behavior or assertions, or generate tests against coverage criteria. It is particularly relevant when I/O equivalence with a language such as Verilog matters. It is a poorer fit for users who require a graphical interface, need a different analysis model than bounded loop unwinding, or do not want to install an external solver when one of those solvers is needed.

For questions, the project directs users to Daniel Kroening and provides a CProver Support Google Group. That offers a project-specific route for support, though the software’s license disclaims warranties.

Pros and cons

Pros

• Free under a BSD 4-clause license: there is no plan fee to add this specialist checker to a workflow.
• Concrete checks and test generation: memory safety, undefined behavior, assertions and multiple coverage-oriented test criteria address practical verification tasks.
• Substantial C/C++ feature coverage: support for arrays, pointers, dynamic memory and selected C++ constructs broadens its relevance beyond minimal examples.
• Built-in solver plus external options: the MiniSat-based solver provides an included route, while supported external solvers add alternatives for teams prepared to install them.

Cons

• Bounded analysis: loop unwinding constrains what the verification result covers, so it is not a universal proof over unbounded execution.
• No graphical interface on Windows or macOS: users must be comfortable with command-line operation, and Windows use adds the Visual Studio Command Prompt requirement.
• External solver setup: Boolector, CVC5 and Z3 require separate installation.
• License disclaimer: the BSD 4-clause license supplies the software as is and disclaims warranties and liability.

Alternatives

For a broader comparison, see C and C++ Static Analysis Tools.

• MATLAB Grader is the better fit for MATLAB work or a web-capable platform mix; its free use requires a current MATLAB license under maintenance, and LMS integration requires a qualifying academic license.
• Infer is another free static-analysis option for supported programming languages, distributed as a binary, source build or Docker image.
• Qodana suits teams seeking a freemium offering with a free trial and web or API platforms; its Community plan is billed free per active contributor per month.
• Semgrep Code is worth considering for a free edition that combines code and supply-chain coverage, with caps of 10 repositories, 10 contributors and 60 AI credits.
• Clang Static Analyzer is a free, open-source alternative for C, C++ and Objective-C across Linux, macOS and Windows.
• Flawfinder is a free GPL-2.0+ option for readers considering another open-source tool.
• Parasoft SOAtest is a paid alternative with a free plan and trial; its SOAtest plan uses custom pricing based on business needs.
• Squish is a paid alternative with a free trial and no free plan.

Verdict

Choose CBMC if you need free, property-focused checking or coverage-driven test generation for C and C++ and are prepared to work at the command line. Its included solver and substantial language coverage make it a capable specialist option. Look elsewhere if you need a GUI or require assurance beyond the bounds of loop-unwound analysis.