chore: reorg

__ffi/live-reload-rust/greet-rs-2/src/main.rs

@@ -0,0 +1,36 @@
+use std::{ffi::c_void, ffi::CString, os::raw::c_char, os::raw::c_int};
+
+#[link(name = "dl")]
+extern "C" {
+    fn dlopen(path: *const c_char, flags: c_int) -> *const c_void;
+    fn dlsym(handle: *const c_void, name: *const c_char) -> *const c_void;
+    fn dlclose(handle: *const c_void);
+}
+
+// had to look that one up in `dlfcn.h`
+// in C, it's a #define. in Rust, it's a proper constant
+pub const RTLD_LAZY: c_int = 0x00001;
+
+fn main() {
+    let lib_name = CString::new("../libgreet.so").unwrap();
+    let lib = unsafe { dlopen(lib_name.as_ptr(), RTLD_LAZY) };
+    if lib.is_null() {
+        panic!("could not open library");
+    }
+
+    let greet_name = CString::new("greet").unwrap();
+    let greet = unsafe { dlsym(lib, greet_name.as_ptr()) };
+
+    type Greet = unsafe extern "C" fn(name: *const c_char);
+    use std::mem::transmute;
+    let greet: Greet = unsafe { transmute(greet) };
+
+    let name = CString::new("fresh coffee").unwrap();
+    unsafe {
+        greet(name.as_ptr());
+    }
+
+    unsafe {
+        dlclose(lib);
+    }
+}