Frequently Asked Question

What is the difference between glibc and musl?

Every Linux program, even ls, links against a C standard library that provides the thin wrapper around system calls (open, read, printf, malloc, and so on). The overwhelming default is glibc, the GNU C Library, which has been developed under the FSF umbrella since the early 1990s. It is feature-rich, deeply tested, and assumed by most binary distributions of software.

musl is a much smaller reimplementation, first released in 2011, with goals of correctness, simplicity, static-linking friendliness, and a clear (MIT) licence. It produces smaller binaries with fewer hidden runtime dependencies, which is why Alpine Linux and many container images choose it. The trade-off is that some glibc-specific behaviour, locale handling, NSS plugins, certain DNS edge cases, dlopen quirks; differs subtly, so binaries built against glibc may not run on musl without recompilation. A few distributions, notably Void Linux musl, provide a full general-purpose system on musl outside of Alpine.