[$] Truly portable C applications Programming language polyglots are files that are valid programs in multiple languages, and do different things in each. While polyglots are normally nothing more than a curiosity, the <a href="https://justine.lol/cosmopolitan/index.html" rel="nofollow"> Cosmopolitan Libc</a> project has been trying to put them to a novel use: producing native, multi-platform binaries that run directly on several operating systems and architectures. There are still some rough edges with the project's approach, but it is generally possible to build C programs into a polyglot format with with minimal tweaking. https://lwn.net/Articles/997238/