diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index b0921f9..976c19a 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,11 @@
 2019-11-26  Tom Tromey  <tromey@adacore.com>
 
+	* windows-nat.c (windows_nat::handle_output_debug_string):
+	Rename.  No longer static.
+	* nat/windows-nat.h (handle_output_debug_string): Declare.
+
+2019-11-26  Tom Tromey  <tromey@adacore.com>
+
 	* windows-nat.c (current_process_handle, current_process_id)
 	(main_thread_id, last_sig, current_event, last_wait_event)
 	(current_windows_thread, desired_stop_thread_id, pending_stops)
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 8349b8d..bd20f14 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,11 @@
 2019-11-26  Tom Tromey  <tromey@adacore.com>
 
+	* win32-low.c (handle_output_debug_string): Add parameter.  Change
+	return type.
+	(win32_kill, get_child_debug_event): Update.
+
+2019-11-26  Tom Tromey  <tromey@adacore.com>
+
 	* win32-low.c (current_process_handle, current_process_id)
 	(main_thread_id, last_sig, current_event): Move to
 	nat/windows-nat.c.
diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index 4cf60b2..7825630 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -722,9 +722,10 @@
 	 (int) err, strwinerror (err));
 }
 
-/* Handle OUTPUT_DEBUG_STRING_EVENT from child process.  */
-static void
-handle_output_debug_string (void)
+/* See nat/windows-nat.h.  */
+
+int
+windows_nat::handle_output_debug_string (struct target_waitstatus *ourstatus)
 {
 #define READ_BUFFER_LEN 1024
   CORE_ADDR addr;
@@ -732,7 +733,7 @@
   DWORD nbytes = current_event.u.DebugString.nDebugStringLength;
 
   if (nbytes == 0)
-    return;
+    return 0;
 
   if (nbytes > READ_BUFFER_LEN)
     nbytes = READ_BUFFER_LEN;
@@ -745,13 +746,13 @@
 	 in Unicode.  */
       WCHAR buffer[(READ_BUFFER_LEN + 1) / sizeof (WCHAR)] = { 0 };
       if (read_inferior_memory (addr, (unsigned char *) buffer, nbytes) != 0)
-	return;
+	return 0;
       wcstombs (s, buffer, (nbytes + 1) / sizeof (WCHAR));
     }
   else
     {
       if (read_inferior_memory (addr, (unsigned char *) s, nbytes) != 0)
-	return;
+	return 0;
     }
 
   if (!startswith (s, "cYg"))
@@ -759,12 +760,14 @@
       if (!server_waiting)
 	{
 	  OUTMSG2(("%s", s));
-	  return;
+	  return 0;
 	}
 
       monitor_output (s);
     }
 #undef READ_BUFFER_LEN
+
+  return 0;
 }
 
 static void
@@ -792,7 +795,7 @@
       if (current_event.dwDebugEventCode == EXIT_PROCESS_DEBUG_EVENT)
 	break;
       else if (current_event.dwDebugEventCode == OUTPUT_DEBUG_STRING_EVENT)
-	handle_output_debug_string ();
+	handle_output_debug_string (nullptr);
     }
 
   win32_clear_inferiors ();
@@ -1473,7 +1476,7 @@
 		"for pid=%u tid=%x\n",
 		(unsigned) current_event.dwProcessId,
 		(unsigned) current_event.dwThreadId));
-      handle_output_debug_string ();
+      handle_output_debug_string (nullptr);
       break;
 
     default:
diff --git a/gdb/nat/windows-nat.h b/gdb/nat/windows-nat.h
index de53f2f..01c647e 100644
--- a/gdb/nat/windows-nat.h
+++ b/gdb/nat/windows-nat.h
@@ -107,6 +107,14 @@
 extern windows_thread_info *thread_rec (ptid_t ptid,
 					thread_disposition_type disposition);
 
+
+/* Handle OUTPUT_DEBUG_STRING_EVENT from child process.  Updates
+   OURSTATUS and returns the thread id if this represents a thread
+   change (this is specific to Cygwin), otherwise 0.
+
+   This function must be supplied by the embedding application.  */
+extern int handle_output_debug_string (struct target_waitstatus *ourstatus);
+
 /* Currently executing process */
 extern HANDLE current_process_handle;
 extern DWORD current_process_id;
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index fad3952..083e05b 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -900,11 +900,10 @@
   CloseHandle ((HANDLE) event_id);
 }
 
-/* Handle DEBUG_STRING output from child process.
-   Cygwin prepends its messages with a "cygwin:".  Interpret this as
-   a Cygwin signal.  Otherwise just print the string as a warning.  */
-static int
-handle_output_debug_string (struct target_waitstatus *ourstatus)
+/* See nat/windows-nat.h.  */
+
+int
+windows_nat::handle_output_debug_string (struct target_waitstatus *ourstatus)
 {
   gdb::unique_xmalloc_ptr<char> s;
   int retval = 0;
