Calling a C function from Rust

Cargo.toml

[package]
name = "remacs"
version = "0.1.0"
authors = ["Wilfred Hughes <me@wilfred.me.uk>"]

[lib]
crate-type = ["staticlib"]

compiling

~/projects/remacs/rust_src $ cargo build --release                                
   Compiling libc v0.2.17
   Compiling remacs v0.1.0 (file:///home/wilfred/projects/remacs/rust_src)
note: link against the following native artifacts when linking against this static library

note: the order and any duplication can be significant on some platforms, and so may need to be preserved

note: library: dl

note: library: pthread

note: library: gcc_s

note: library: c

note: library: m

note: library: rt

note: library: util

    Finished release [optimized] target(s) in 1.48 secs
~/projects/remacs/rust_src $ gcc -Wall -Wextra -L target/release/ -l remacs demo.c
/tmp/ccuJe0ht.o: In function `main':
demo.c:(.text+0xa): undefined reference to `rust_hello'
collect2: error: ld returned 1 exit status

demo.c

#include <stdio.h>

void rust_hello();

int main() {
    rust_hello();
    printf("hello world!\n");
    return 0;
}

lib.rs

#[no_mangle]
pub unsafe extern "C" fn rust_hello() {
    println!("hello from rust!");
}

title is wrong please edit, came from google

title is wrong please edit, came from google

I think I must have been referring to demo.c calling a Rust function from C and ignoring the fact that println was the C fxn he was referring to, not sure why I felt it necessary to make the comment where I did (probably was tired!)... good lookin out.