Updated 'src/advanced_features/unsafe.md'.

projects/my_rust_lib/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "my_rust_lib"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+name = "my_rust_lib"
+crate-type = ["cdylib"]
+
+[dependencies]

projects/my_rust_lib/main.c

@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+extern void call_from_c();
+
+int main () {
+    call_from_c();
+
+    return 0;
+}

projects/my_rust_lib/src/lib.rs

@@ -0,0 +1,5 @@
+#[unsafe(no_mangle)]
+pub extern "C" fn call_from_c() {
+    println!("刚刚从 C 调用了 Rust 函数！");
+}
+