Welcome to Fil-C, an actively supported memory safe implementation of the C and C++ programming languages you already know and love. What is Fil-C? Fil-C is a fanatically compatible memory-safe (https://fil-c.org/gimso.html) implementation of C and C++. Lots of software compiles and runs with Fil-C with zero or minimal changes. All memory safety errors are caught as Fil-C panics. Fil-C achieves this using a combination of concurrent garbage collection (https://fil-c.org/fugc.html) and invisible capabilities (InvisiCaps (https://fil-c.org/invisicaps.html)). Every possibly-unsafe C and C++ operation is checked. Fil-C has no unsafe statement and only limited FFI to unsafe code. Key Features • Memory Safety: Advanced runtime checks to prevent exploitable memory safety errors (https://fil-c.org/invisicaps_by_example.html). Unlike other approaches to increasing the safety of C, Fil-C achieves complete memory safety (https://fil-c.org/gimso.html) with zero escape hatches. • C and C++ Compatibility: Your C or C++ software most likely compiles and runs in Fil-C with zero changes. Many open source programs (https://fil-c.org/programs_that_work.html), including CPython, OpenSSH, GNU Emacs, and Wayland work great in Fil-C. Even advanced features like threads, atomics, exceptions, signal handling, longjmp/setjmp, and shared memory (mmap style or Sys-V style) work. It's possible to run a totally memory safe Linux userland (https://fil-c.org/pizlix.html), including GUI, with Fil-C. Fil-C even supports memory safe inline assembly (https://fil-c.org/inlineasm.html). • Modern Tooling: Compiler (https://fil-c.org/compiler.html) is based on a recent version of clang (20.1.8), supports all clang extensions, most GCC extensions, and works with existing C/C++ build systems (make, autotools, cmake, meson, etc). Quick Links • Download Fil-C 0.679 (https://github.com/pizlonator/fil-c/releases/tag/v0.679) (released 7 June 2026) • Installation Guide (https://fil-c.org/installation.html) • How Fil-C Works (https://fil-c.org/how.html) • InvisiCaps: The Fil-C Capability Model (https://fil-c.org/invisicaps.html) • Fil's Unbelievable Garbage Collector (https://fil-c.org/fugc.html) • More Documentation (https://fil-c.org/documentation.html) License Fil-C's compiler is licensed under Apache 2 (https://github.com/pizlonator/fil-c/blob/deluge/LLVM-LICENSE.txt). Fil-C's runtime is licensed under BSD 2-clause (https://github.com/pizlonator/fil-c/blob/deluge/libpas/LICENSE.txt). Fil-C has two standard libraries; musl is used in the pizfix slice (https://fil-c.org/pizfix.html) binary distributions and is licensed under MIT (https://github.com/pizlonator/fil-c/blob/deluge/projects/usermusl/COPYRIGHT), while glibc is available in the /opt/fil (https://fil-c.org/optfil.html) binary distributions and in Pizlix (https://fil-c.org/pizlix.html) and is licensed under LGPL 2.1 (https://github.com/pizlonator/fil-c/blob/deluge/projects/user-glibc-2.40/COPYING.LIB). Community Join the Fil-C Discord community (https://discord.gg/dPyNUaeajg) to discuss the language implementation, share projects, and contribute to its development.