CBMC

CBMC is a bounded model checker for C and C++ that verifies program properties and can generate tests. It suits developers who need checks such as memory-safety verification or assertion checking in a command-line workflow. Its free license and broad C support are compelling, but loop unwinding and separately installed external solvers are important practical constraints.

Overview

CBMC analyzes bounded program behavior by unwinding loops and passing the resulting equation to a decision procedure. That gives C and C++ developers a way to check specified properties, including memory safety, undefined behavior and user assertions. The method is bounded: users should choose it for this style of analysis, rather than assume it proves properties across unbounded execution.

It can also check I/O equivalence between C or C++ and languages such as Verilog. That makes it relevant to work involving software and hardware interfaces, though the tool remains a command-line checker rather than a graphical review environment.

Key features

• Memory and behavior checks: CBMC checks array bounds, pointer use, several forms of undefined behavior and user-specified assertions. These checks target concrete classes of defects, making the tool useful when those properties matter more than a general-purpose developer interface.
• C and C++ support: It supports C89, C99, most of C11 and C17, and many GCC, Clang and Visual Studio extensions. Supported features include multidimensional and dynamically sized arrays, dynamic memory, nondeterminism, assumptions and assertions; C++ support includes classes, templates and selected STL containers. This breadth helps with varied codebases, but does not mean every language feature is covered.
• Solver choices: A MiniSat-based bit-vector solver is included, so users can begin without configuring an external solver. Boolector, CVC5 and Z3 are also supported, but must be installed separately.
• Test generation: CBMC can generate tests for branch, decision, path and MC/DC coverage. This extends its usefulness beyond checking properties when coverage-oriented test cases are also needed.

Pricing

CBMC costs nothing under a BSD 4-clause license, with the command-line tool included. There is no free trial because the software is free. The license provides the software “AS IS” and disclaims warranties and liability, so organizations should account for those terms when deciding whether it fits their requirements.

Platforms

CBMC supports Linux, macOS and Windows. Debian and Ubuntu package it, and Fedora users can install it with dnf. The Windows release is an x64 command-line binary run from the Visual Studio Command Prompt; macOS is also command-line only. Users seeking a GUI should look elsewhere on either platform.

Who it's for

CBMC is best suited to C and C++ developers who want bounded checks for memory safety, undefined behavior or assertions, and to teams that need coverage-based test generation or C/C++ I/O equivalence checks with languages such as Verilog. It is a weaker fit for users who require a graphical interface, broad language coverage beyond its supported C and C++ features, or external solver integration without separate installation.

Pros and cons

• Pro: The included MiniSat-based solver and free BSD-licensed tool provide a usable starting point without buying a plan.
• Pro: Checks for memory safety, undefined behavior and assertions address specific correctness risks in C and C++ programs.
• Pro: Test generation for several coverage criteria and cross-language I/O equivalence add uses beyond defect checking alone.
• Con: Verification relies on loop unwinding, so CBMC is a bounded checker, not a universal guarantee about all executions.
• Con: External solvers require separate installation, and Windows and macOS users get no GUI.

Alternatives

For a broader comparison, see C and C++ Static Analysis Tools. Consider Infer instead if you want free static analysis with Linux, macOS, self-hosted and web platform options. MATLAB Grader may fit better when MATLAB-based grading is the goal; its free plan requires a MATLAB license current under maintenance, and LMS integration requires a qualifying academic license.

Qodana is another option if a freemium tool with a free trial and API, web and self-hosted platform options is a better match. Semgrep Code may suit teams seeking code and supply-chain coverage; its Free Edition is capped at 10 repositories, 10 contributors and 60 AI credits.

Choose Clang Static Analyzer for an open-source analyzer covering C, C++ and Objective-C. Flawfinder is a free GPL-2.0+ alternative. Parasoft SOAtest offers tailored pricing based on business needs. CodeChecker is another free option.

Verdict

Choose CBMC if you need free, bounded verification and test generation for C and C++ and are comfortable working at the command line. Its focused checks and included solver make it a practical option for code where memory safety, assertions or coverage matter. Look elsewhere if you need a GUI or want external solvers to work without installing them separately.