https://github.com/nagisa/rust_libloading/issues/5

app/src/lib.rs

@@ -1,7 +1,4 @@
-use std::ffi::CString;
-use std::os::raw::c_char;
-
 #[no_mangle]
-pub fn get_message() -> *mut c_char {
-    CString::new(String::from("hello world")).unwrap().into_raw()
+pub unsafe extern "C" fn testing() {
+    println!("YES!");
 }

main/Cargo.toml

@@ -5,3 +5,6 @@ authors = ["Damien Radtke <[email protected]>"]
 
 [dependencies.app]
 path = "../app"
+
+[dependencies]
+libloading = "0.4.3"

main/src/main.rs

@@ -1,38 +1,43 @@
-use std::ffi::CString;
-use std::os::raw;
-use std::{thread, time};
-
-const RTLD_NOW: raw::c_int = 2;
-const LIB_PATH: &'static str = "../app/target/debug/libapp.dylib";
-
-extern "C" {
-    fn dlopen(filename: *const raw::c_char, flags: raw::c_int) -> *mut raw::c_void;
-    fn dlclose(handle: *mut raw::c_void) -> raw::c_int;
-    fn dlsym(handle: *mut raw::c_void, symbol: *const raw::c_char) -> *mut raw::c_void;
-    fn dlerror() -> *mut raw::c_char;
-}
+// extern crate libloading;
+
+// use std::os::raw;
+// use std::{thread, time};
+// use libloading::{Library, Symbol};
+
+// const LIB_PATH: &'static str = "../app/target/debug/libapp.dylib";
+
+// extern "C" {
+//     fn _dyld_image_count() -> u32;
+// }
+
+// fn main() {
+//     loop {
+//         unsafe {
+//             let i = _dyld_image_count();
+//             println!("{}", i);
+//         }
+
+//         thread::sleep(time::Duration::from_secs(1));
+
+//         let lib = Library::new(LIB_PATH)
+//             .expect("Library not found");
+
+//         unsafe {
+//             let init: Symbol<unsafe extern "C" fn()> =
+//                 lib.get(b"init").expect("Symbol not found");
+//             init()
+//         };
+//     }
+// }
+
+extern crate libloading;
+
+use libloading::{Library, Symbol};
 
 fn main() {
-    loop {
-        unsafe {
-            thread::sleep(time::Duration::from_secs(1));
-            let handle = dlopen(CString::new(LIB_PATH).unwrap().into_raw(), RTLD_NOW);
-
-            let symbol = b"get_message";
-            let get_message = dlsym(handle, CString::new(&symbol[..]).unwrap().into_raw());
-            if get_message.is_null() {
-                println!("Failed to retrieve get_message symbol: {}", CString::from_raw(dlerror()).into_string().expect("Failed to retrieve dlerror"));
-                return;
-            }
-
-            let func = ::std::mem::transmute::<*mut raw::c_void, unsafe extern fn() -> *mut raw::c_char>(get_message);
-            let message = CString::from_raw(func()).into_string().unwrap();
-            println!("Message: {}", message);
-
-            if dlclose(handle) != 0 {
-                println!("Failed to close handle: {}", CString::from_raw(dlerror()).into_string().expect("Failed to retrieve dlerror"));
-                return;
-            }
-        }
-    }
+    let lib = Library::new("../app/target/debug/libapp.dylib").unwrap();
+    let sym: Symbol<unsafe extern "C" fn() -> ()> = unsafe { lib.get(b"testing") }.unwrap();
+    unsafe {
+        sym()
+    };
 }