锈libc :: setsockopt强制转换为c_void

Question

我正尝试致电setsockopt，但无法找出对c_void的演员表。 IP_HDRINCL不在nix或socket的板条箱中，因此我必须使用libc。我以How to set the socket option SO_REUSEPORT in Rust?

为例

let trueval: c_int = 1;
let ret = setsockopt(mysocket, IPPROTO_IP, IP_HDRINCL, &trueval as *const _ as *const c_void, mem::size_of_val(&trueval) as socklen_t);

error: expected expression, found keyword `const`
  --> src/igmp.rs:30:97
   |
30 |         let ret = setsockopt(mysocket, IPPROTO_IP, IP_HDRINCL, &trueval as *const _ *const c_void, mem::size_of_val(&trueval) as socklen_t);
   |                                                                                      ^^^^^ expected expression

Answer 1

将trueval更改为u8即可使代码正常工作。