runng-sys

Rust FFI bindings to NNG.

Usage

Version of this crate tracks NNG: <NNG_version>-rc.<crate_version> (e.g. 1.1.1-rc.2).

To use the latest crate for the most recent stable version of NNG (1.1.1), in Cargo.toml:

runng-sys = "1.1.1-rc"

For a more ergonomic API to NNG see runng.

Examples

use runng_sys::*;
use std::ffi::CString;

#[test]
fn it_works() {
    unsafe {
        let url = CString::new("inproc://test").unwrap();
        let url = url.as_bytes_with_nul().as_ptr() as *const i8;

        // Reply socket
        let mut rep_socket = nng_socket { id: 0 };
        assert_eq!(0, nng_rep0_open(&mut rep_socket));
        assert_eq!(0, nng_listen(rep_socket, url, std::ptr::null_mut(), 0));

        // Request socket
        let mut req_socket = nng_socket { id: 0 };
        assert_eq!(0, nng_req0_open(&mut req_socket));
        assert_eq!(0, nng_dial(req_socket, url, std::ptr::null_mut(), 0));

        // Send message
        let mut req_msg: *mut nng_msg = std::ptr::null_mut();
        assert_eq!(0, nng_msg_alloc(&mut req_msg, 0));
        // Add a value to the body of the message
        let val = 0x12345678;
        assert_eq!(0, nng_msg_append_u32(req_msg, val));
        assert_eq!(0, nng_sendmsg(req_socket, req_msg, 0));

        // Receive it
        let mut recv_msg: *mut nng_msg = std::ptr::null_mut();
        assert_eq!(0, nng_recvmsg(rep_socket, &mut recv_msg, 0));
        // Remove our value from the body of the received message
        let mut recv_val: u32 = 0;
        assert_eq!(0, nng_msg_trim_u32(recv_msg, &mut recv_val));
        assert_eq!(val, recv_val);
        // Can't do this because nng uses network order (big-endian)
        //assert_eq!(val, *(nng_msg_body(recv_msg) as *const u32));

        nng_close(req_socket);
        nng_close(rep_socket);
    }
}