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Tech riderRev. 4 Oct 2026

Csmith

Ch 096.9of 27 Fuzz Testing Software
  1. 1Runs onLinux, Windows
  2. 2CostsFree plan
  3. 3Input generation methodsgeneration
  4. 4Target typesC programs; C++ programs; compilers
  5. 5Execution modelocal
  6. 6Supported languagesC; C++
  7. 7CI/CD supportYes
7 lines stated Written from the maker's own pages: github.com
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Overview

Csmith is ranked #9 of 27 in fuzz testing software on Specifiction. It runs on Linux, Windows. There is a free plan.

Csmith plans and pricing

All plans
Csmith Free Open-source C program generator github.com · 4 Oct 2026

Compared on fuzz testing software

Free plan
Yesgithub.com
Input generation methods
generationgithub.com
Target types
C programs; C++ programs; compilersgithub.com
Execution mode
localgithub.com
Supported languages
C; C++github.com
CI/CD support
Yesgithub.com

Facts

Purpose
Csmith generates random C programs to find compiler bugs using differential testing.github.com · 4 Oct 2026
Safe output
Generated C programs are free of undefined behaviors and include per-program statistics.github.com · 4 Oct 2026
Other use
The project suggests using Csmith to create a C-program test suite when users do not want to write one themselves.github.com · 4 Oct 2026
Compiler workflow
The README demonstrates compiling generated programs with GCC and Clang and comparing their outputs to identify compiler bugs.github.com · 4 Oct 2026
Customization
Command-line options shown by `csmith -h` and `csmith -hh` customize random generation.github.com · 4 Oct 2026
Execution limit
Generated programs might contain infinite loops, and the README recommends applying timeouts to their execution.github.com · 4 Oct 2026
Linux build
The Ubuntu build instructions list g++, CMake, and m4 as prerequisites and use CMake and make to install from source.github.com · 4 Oct 2026
Windows build
The project documents building on Windows with Visual Studio or WSL.github.com · 4 Oct 2026
Build compatibility
The INSTALL file says Csmith should build on most modern machines with a C++ compiler.github.com · 4 Oct 2026
License
The repository includes a COPYING license file.github.com · 4 Oct 2026
Support
The project directs users to GitHub issues for bug reports and suggestions and provides a mailing list for discussion.github.com · 4 Oct 2026
Support response
The maintainers say they maintain Csmith in their discretionary time and responses to bug reports or feature requests may be delayed.github.com · 4 Oct 2026
Origin
Csmith was originally developed at the University of Utah as part of a compiler-testing research project and was open-sourced in 2009.github.com · 4 Oct 2026

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