diff --git a/doc/go1.16.html b/doc/go1.16.html
index a2f3989..92cadff 100644
--- a/doc/go1.16.html
+++ b/doc/go1.16.html
@@ -501,6 +501,10 @@
     <p><!-- CL 261917 -->
       <a href="/pkg/syscall/#SysProcAttr"><code>SysProcAttr</code></a> on Windows has a new NoInheritHandles field that disables inheriting handles when creating a new process.
     </p>
+
+    <p><!-- CL 269761, golang.org/issue/42584 -->
+      <a href="/pkg/syscall/#DLLError"><code>DLLError</code></a> on Windows now has an Unwrap function for unwrapping its underlying error.
+    </p>
   </dd>
 </dl><!-- syscall -->
 
diff --git a/src/syscall/dll_windows.go b/src/syscall/dll_windows.go
index c54feec..d99da00 100644
--- a/src/syscall/dll_windows.go
+++ b/src/syscall/dll_windows.go
@@ -20,6 +20,8 @@
 
 func (e *DLLError) Error() string { return e.Msg }
 
+func (e *DLLError) Unwrap() error { return e.Err }
+
 // Implemented in ../runtime/syscall_windows.go.
 
 func Syscall(trap, nargs, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)