The C libffi library provides two main facilities: assembling calls
to functions dynamically, and creating closures that can be called
as ordinary C functions. In Rust, the latter means that we can turn
a Rust lambda (or any object implementing Fn/FnMut) into an
ordinary C function pointer that we can pass as a callback to C.
The easiest way to use this library is via the high layer module, but
more flexibility (and less checking) is provided by the middle and
low layers.
It’s on crates.io, but before you build it, make sure you have the dependencies installed first:
An up-to-date version of C libffi Version 3.2.1 is known to work. Earlier versions, such as the versions that come with Mac OS and Fedora, are known not to; neither will the version installed by Homebrew (3.0.13).
pkg-config,
which you probably already have if you’re on Linux. For Mac users,
the version installed by Homebrew is up to date. (I don’t know how
this works on Windows; contact me if you’d like to help figure it
out.)
Then add
toml
[dependencies]
libffi = "0.3"
to your Cargo.toml and
rust
extern crate libffi;
to your crate root.