c_void in std::ffi - Rust (original) (raw)

Enum c_void

1.30.0 · Source

#[repr(u8)]

pub enum c_void {
    // some variants omitted
}

Expand description

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 compiler down to 1.1.0. After Rust 1.30.0, it was re-exported by this definition. For more information, please read RFC 2521.

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