From 3e4af3cd8c7d4e09f6074f475727e0cbeb297462 Mon Sep 17 00:00:00 2001
From: Pierre Ossman <ossman@cendio.se>
Date: Thu, 9 Oct 2014 12:52:05 +0000
Subject: [PATCH] Make sure we unregister for clipboard notifications on exit
 on Windows. This is necessary because Windows doesn't implicitly clean up
 when a process dies, and we cannot trust applications to always explicitly
 unregister.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10367 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 src/Fl_win32.cxx | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/Fl_win32.cxx b/src/Fl_win32.cxx
index fe051e363..0872981f5 100644
--- a/src/Fl_win32.cxx
+++ b/src/Fl_win32.cxx
@@ -472,6 +472,11 @@ public:
     OleUninitialize();
     fl_brush_action(1);
     fl_cleanup_dc_list();
+    // This is actually too late in the cleanup process to remove the
+    // clipboard notifications, but we have no earlier hook so we try
+    // to work around it anyway.
+    if (clipboard_wnd != NULL)
+      fl_clipboard_notify_untarget(clipboard_wnd);
   }
 };
 static Fl_Win32_At_Exit win32_at_exit;
@@ -812,7 +817,30 @@ static void fl_clipboard_notify_untarget(HWND wnd) {
   if (wnd != clipboard_wnd)
     return;
 
-  ChangeClipboardChain(wnd, next_clipboard_wnd);
+  // We might be called late in the cleanup where Windows has already
+  // implicitly destroyed our clipboard window. At that point we need
+  // to do some extra work to manually repair the clipboard chain.
+  if (IsWindow(wnd))
+    ChangeClipboardChain(wnd, next_clipboard_wnd);
+  else {
+    HWND tmp, head;
+
+    tmp = CreateWindow("STATIC", "Temporary FLTK Clipboard Window", 0,
+                       0, 0, 0, 0, HWND_MESSAGE, NULL, NULL, NULL);
+    if (tmp == NULL)
+      return;
+
+    head = SetClipboardViewer(tmp);
+    if (head == NULL)
+      ChangeClipboardChain(tmp, next_clipboard_wnd);
+    else {
+      SendMessage(head, WM_CHANGECBCHAIN, (WPARAM)wnd, (LPARAM)next_clipboard_wnd);
+      ChangeClipboardChain(tmp, head);
+    }
+
+    DestroyWindow(tmp);
+  }
+
   clipboard_wnd = next_clipboard_wnd = 0;
 }