Inside: Racket C API

This manual describes the C interface of Racket’s runtime system, which varies depending on the variant of Racket (see Racket Virtual Machine Implementations): the CS variant of Racket has one interface, while the BC (3m and CGC) variants of Racket have another.

The C interface is relevant to some degree when interacting with foreign libraries as described in The Racket Foreign Interface. Even though interactions with foreign code are constructed in pure Racket using the ffi/unsafe module, many details of representations, memory management, and concurrency are described here. This manual also describes embedding the Racket run-time system in larger programs and extending Racket directly with C-implemented libraries.