add trivial examples

examples/libc_test/Cargo.lock

@@ -0,0 +1,16 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "libc"
+version = "0.2.186"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68ab91017fe16c622486840e4c83c9a37afeff978bd239b5293d61ece587de66"
+
+[[package]]
+name = "libc_test"
+version = "0.1.0"
+dependencies = [
+ "libc",
+]

examples/libc_test/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "libc_test"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+libc = "0.2.186"

examples/libc_test/src/main.rs

@@ -0,0 +1,15 @@
+extern crate libc;
+
+use std::ffi::CStr;
+fn main() {
+    unsafe {
+        let buf: *mut libc::utsname = libc::malloc(size_of::<libc::utsname>()) as *mut libc::utsname;
+        if buf.is_null() {
+            panic!("failed to allocate buf");
+        }
+        libc::uname(buf);
+        let sysname: &CStr = CStr::from_ptr((*buf).sysname.as_ptr());
+        println!("Hello, {}!", sysname.to_str().unwrap());
+        libc::free(buf as *mut core::ffi::c_void);
+    }
+}