dlopen2 0.8.2

Library for opening and operating on dynamic link libraries (also known as shared objects or shared libraries).
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61

mod commons;

use commons::{SomeData, example_lib_path};
use dlopen2::raw::Library;
use std::ffi::CStr;
use std::os::raw::{c_char, c_int};

fn main() {
    let lib_path = example_lib_path();
    let lib = Library::open(lib_path).expect("Could not open library");

    //get several symbols and play around
    let rust_fun_print_something: fn() =
        unsafe { lib.symbol_cstr(c"rust_fun_print_something") }.unwrap();
    rust_fun_print_something();

    let rust_fun_add_one: fn(i32) -> i32 = unsafe { lib.symbol_cstr(c"rust_fun_add_one") }.unwrap();
    println!(" 5+1={}", rust_fun_add_one(5));

    let c_fun_print_something_else: unsafe extern "C" fn() =
        unsafe { lib.symbol_cstr(c"c_fun_print_something_else") }.unwrap();
    unsafe { c_fun_print_something_else() };

    let c_fun_add_two: unsafe extern "C" fn(c_int) -> c_int =
        unsafe { lib.symbol_cstr(c"c_fun_add_two") }.unwrap();
    println!("2+2={}", unsafe { c_fun_add_two(2) });

    let rust_i32: &i32 = unsafe { lib.symbol_cstr(c"rust_i32") }.unwrap();
    println!("const rust i32 value: {rust_i32}");

    let rust_i32_mut: &mut i32 = unsafe { lib.symbol_cstr(c"rust_i32_mut") }.unwrap();
    println!("mutable rust i32 value: {rust_i32_mut}");

    *rust_i32_mut = 55;
    //for a change use pointer to obtain its value
    let rust_i32_ptr: *const i32 = unsafe { lib.symbol_cstr(c"rust_i32_mut") }.unwrap();
    println!("after change: {}", unsafe { *rust_i32_ptr });

    //the same with C
    let c_int: &c_int = unsafe { lib.symbol_cstr(c"c_int") }.unwrap();
    println!("c_int={c_int}");

    //now static c struct

    let c_struct: &SomeData = unsafe { lib.symbol_cstr(c"c_struct") }.unwrap();
    println!(
        "c struct first: {}, second:{}",
        c_struct.first, c_struct.second
    );

    //let's play with strings

    let rust_str: &&str = unsafe { lib.symbol_cstr(c"rust_str") }.unwrap();
    println!("Rust says: {}", *rust_str);

    let c_const_char_ptr: *const c_char = unsafe { lib.symbol_cstr(c"c_const_char_ptr") }.unwrap();
    let converted = unsafe { CStr::from_ptr(c_const_char_ptr) }
        .to_str()
        .unwrap();
    println!("And now C says: {converted}");
}