doc addition

Author: devnexen

src/unistd.rs

@@ -4016,6 +4016,10 @@ feature! {
 
 /// Close all the file descriptor from a given range.
 /// An optional flag can be applied to modify its behavior.
+///
+/// # Safety
+///
+/// This function as there are risks of double closes on the file descriptors.
 #[cfg(any(
     all(target_os = "linux", target_env = "gnu"),
     target_os = "freebsd"

test/test_unistd.rs

@@ -1410,8 +1410,13 @@ fn test_close_range() {
     for tf in &mut tempfile {
         let _ = tf.write_all(CONTENTS);
     }
-    let areclosed =
-        unsafe { close_range(tempfile[0].as_file().as_fd(), tempfile[2].as_file().as_fd(), CloseRangeFlags::CLOSE_RANGE_CLOEXEC) };
+    let areclosed = unsafe {
+        close_range(
+            tempfile[0].as_file().as_fd(),
+            tempfile[2].as_file().as_fd(),
+            CloseRangeFlags::CLOSE_RANGE_CLOEXEC,
+        )
+    };
     assert_eq!(
         areclosed
             .expect("close_range failed")