How to use a shared library written in C from a program written in Rust. ( rust version 0.7. \ host: i686-unknown-linux-gnu ).

libload.sh

# so the lib can be found when the test is run
export LD_LIBRARY_PATH=./:$LD_LIBRARY_PATH
# alternatively put the .so generated after running make someplace where the system will find it

makefile

all:
    gcc -Wall -fPIC -c *.c
    gcc -shared -Wl,-soname,libsilly.so -o libsilly.so *.o
    gcc -Wall -L./ test.c -lsilly -o test
    rustc -L./ test-rust.rs

silly.c

#include <stdio.h>

void silly_run(int num) {
    printf("the silly number is %d\n", num);
}

test-rust.rs

use std::libc::c_int;

#[link_args = "-lsilly"]
extern {
    fn silly_run(num: c_int) -> ();
}

fn main() {
    unsafe { silly_run(5); }
    println("Ran the unsafe code.");
}

test.c

void silly_run(int);

int main() {
    silly_run(5);
    return 0;
}