C Void

Equivalent to C's void type when used as a [pointer].

In essence, *const c_void is equivalent to C's const void* and *mut c_void is equivalent to C's void*. That said, this is not the same as C's void return type, which is Rust's () type.

To model pointers to opaque types in FFI, until extern type is stabilized, it is recommended to use a newtype wrapper around an empty byte array. See the Nomicon for details.

One could use std::os::raw::c_void if they want to support old Rust compilers down to 1.1.0. After Rust 1.30.0, it was re-exported by this definition. For more information, please read RFC 2521.