Added a namespace method to the Node to get the namespace from the node.

examples/parameters.rs

@@ -10,6 +10,7 @@ fn main() -> Result<(), Error> {
 
     println!("node name: {}", node.name()?);
     println!("node fully qualified name: {}", node.fully_qualified_name()?);
+    println!("node namespace: {}", node.namespace()?);
 
     println!("node parameters");
     node.params.iter().for_each(|(k,v)| {

src/lib.rs

@@ -536,6 +536,15 @@ impl Node {
         Ok(s.to_str().unwrap_or("").to_owned())
     }
 
+    pub fn namespace(&self) -> Result<String> {
+        let cstr = unsafe { rcl_node_get_namespace(self.node_handle.as_ref()) };
+        if cstr == std::ptr::null() {
+            return Err(Error::RCL_RET_NODE_INVALID);
+        }
+        let s = unsafe { CStr::from_ptr(cstr as *const i8) };
+        Ok(s.to_str().unwrap_or("").to_owned())
+    }
+
     fn load_params(&mut self) -> Result<()> {
         let ctx = self.context.context_handle.lock().unwrap();
         let mut params: Box<*mut rcl_params_t> = Box::new(std::ptr::null_mut());