NxWM: Add a missing part of the message blocking logic

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@4748 7fd9a85b-ad96-42d3-883c-3090e2eb8679

23 files changed, 121 insertions, 77 deletions

diff --git a/NxWidgets/libnxwidgets/include/ccallback.hxx b/NxWidgets/libnxwidgets/include/ccallback.hxx
index ca3313a9b8..09cb83a8a3 100644
--- a/NxWidgets/libnxwidgets/include/ccallback.hxx
+++ b/NxWidgets/libnxwidgets/include/ccallback.hxx
@@ -195,12 +195,13 @@ namespace NXWidgets
      * callbacks can lead to bad behavior when the callback is executed.
      *
      * @param hwnd. Window handle of the blocked window
-     * @param arg. User provided argument (see nx_openwindow, nx_requestbkgd,
+     * @param arg1. User provided argument (see nx_openwindow, nx_requestbkgd,
      *   nxtk_openwindow, or nxtk_opentoolbar)
+     * @param arg2 - User provided argument (see nx_block or nxtk_block)
      */
 
 #ifdef CONFIG_NX_MULTIUSER
-  static void windowBlocked(NXWINDOW hwnd, FAR void *arg);
+  static void windowBlocked(NXWINDOW hwnd, FAR void *arg1, FAR void *arg2);
 #endif
 
   public:
diff --git a/NxWidgets/libnxwidgets/include/cwidgetcontrol.hxx b/NxWidgets/libnxwidgets/include/cwidgetcontrol.hxx
index 453cc11157..e709271a08 100644
--- a/NxWidgets/libnxwidgets/include/cwidgetcontrol.hxx
+++ b/NxWidgets/libnxwidgets/include/cwidgetcontrol.hxx
@@ -609,15 +609,13 @@ namespace NXWidgets
     * window may be safely closed.  Closing the window prior with pending
     * callbacks can lead to bad behavior when the callback is executed.
     *
-    * @param hwnd. Window handle of the blocked window
-    * @param arg. User provided argument (see nx_openwindow, nx_requestbkgd,
-    *   nxtk_openwindow, or nxtk_opentoolbar)
+    * @param arg - User provided argument (see nx_block or nxtk_block)
     */
 
 #ifdef CONFIG_NX_MULTIUSER
-   inline void windowBlocked(void)
+   inline void windowBlocked(FAR void *arg)
    {
-     m_eventHandlers.raiseBlockedEvent();
+     m_eventHandlers.raiseBlockedEvent(arg);
    }
 #endif
 
diff --git a/NxWidgets/libnxwidgets/include/cwindoweventhandler.hxx b/NxWidgets/libnxwidgets/include/cwindoweventhandler.hxx
index c414abadb7..574c24b551 100644
--- a/NxWidgets/libnxwidgets/include/cwindoweventhandler.hxx
+++ b/NxWidgets/libnxwidgets/include/cwindoweventhandler.hxx
@@ -108,9 +108,11 @@ namespace NXWidgets
 
     /**
      * Handle a NX window blocked event
+     *
+     * @param arg - User provided argument (see nx_block or nxtk_block)
      */
  
-    virtual void handleBlockedEvent(void) { }
+    virtual void handleBlockedEvent(FAR void *arg) { }
   };
 }
 
diff --git a/NxWidgets/libnxwidgets/include/cwindoweventhandlerlist.hxx b/NxWidgets/libnxwidgets/include/cwindoweventhandlerlist.hxx
index d9e17de091..035e6a7b94 100644
--- a/NxWidgets/libnxwidgets/include/cwindoweventhandlerlist.hxx
+++ b/NxWidgets/libnxwidgets/include/cwindoweventhandlerlist.hxx
@@ -39,7 +39,7 @@
 /****************************************************************************
  * Included Files
  ****************************************************************************/
- 
+
 #include <nuttx/config.h>
 
 #include <stdint.h>
@@ -163,9 +163,11 @@ namespace NXWidgets
 
     /**
      * Raise an NX window blocked event.
+     *
+     * @param arg - User provided argument (see nx_block or nxtk_block)
      */
 
-    void raiseBlockedEvent(void);
+    void raiseBlockedEvent(FAR void *arg);
   };
 }
 
diff --git a/NxWidgets/libnxwidgets/src/ccallback.cxx b/NxWidgets/libnxwidgets/src/ccallback.cxx
index 32c5b7d642..b2256c6bb4 100644
--- a/NxWidgets/libnxwidgets/src/ccallback.cxx
+++ b/NxWidgets/libnxwidgets/src/ccallback.cxx
@@ -211,22 +211,23 @@ void CCallback::newKeyboardEvent(NXHANDLE hwnd, uint8_t nCh,
  * callbacks can lead to bad behavior when the callback is executed.
  *
  * @param hwnd. Window handle of the blocked window
- * @param arg. User provided argument (see nx_openwindow, nx_requestbkgd,
+ * @param arg1. User provided argument (see nx_openwindow, nx_requestbkgd,
  *   nxtk_openwindow, or nxtk_opentoolbar)
+ * @param arg2 - User provided argument (see nx_block or nxtk_block)
  */
 
 #ifdef CONFIG_NX_MULTIUSER
-void CCallback::windowBlocked(NXWINDOW hwnd, FAR void *arg)
+void CCallback::windowBlocked(NXWINDOW hwnd, FAR void *arg1, FAR void *arg2)
 {
-  gvdbg("hwnd=%p arg=%p\n", hwnd, arg);
+  gvdbg("hwnd=%p arg1=%p arg2=%p\n", hwnd, arg1, arg2);
 
-  // The argument must be the CWidgetControl instance
+  // The first argument must be the CWidgetControl instance
 
-  CWidgetControl *This = (CWidgetControl *)arg;
+  CWidgetControl *This = (CWidgetControl *)arg1;
 
   // Just forward the callback to the CWidgetControl::windowBlocked method
 
-  This->windowBlocked();
+  This->windowBlocked(arg2);
 }
 #endif
 
diff --git a/NxWidgets/libnxwidgets/src/cwindoweventhandlerlist.cxx b/NxWidgets/libnxwidgets/src/cwindoweventhandlerlist.cxx
index 15b2c65ff4..dfdabcf089 100644
--- a/NxWidgets/libnxwidgets/src/cwindoweventhandlerlist.cxx
+++ b/NxWidgets/libnxwidgets/src/cwindoweventhandlerlist.cxx
@@ -162,12 +162,14 @@ void CWindowEventHandlerList::raiseKeyboardEvent(void)
 
 /**
  * Raise an NX window blocked event.
+ *
+ * @param arg - User provided argument (see nx_block or nxtk_block)
  */
 
-void CWindowEventHandlerList::raiseBlockedEvent(void)
+void CWindowEventHandlerList::raiseBlockedEvent(FAR void *arg)
 {
   for (int i = 0; i < m_eventHandlers.size(); ++i)
     {
-      m_eventHandlers.at(i)->handleBlockedEvent();
+      m_eventHandlers.at(i)->handleBlockedEvent(arg);
     }
 }
diff --git a/NxWidgets/nxwm/include/capplicationwindow.hxx b/NxWidgets/nxwm/include/capplicationwindow.hxx
index 686150d144..46e4e90d29 100644
--- a/NxWidgets/nxwm/include/capplicationwindow.hxx
+++ b/NxWidgets/nxwm/include/capplicationwindow.hxx
@@ -162,9 +162,11 @@ namespace NxWM
     /**
      * Block further activity on this window in preparation for window
      * shutdown.
+     *
+     * @param app. The application to be blocked
      */
 
-    void block(void);
+    void block(IApplication *app);
 
     /**
      * Set the window label
diff --git a/NxWidgets/nxwm/include/cfullscreenwindow.hxx b/NxWidgets/nxwm/include/cfullscreenwindow.hxx
index 1bab37543f..70da9fee5e 100644
--- a/NxWidgets/nxwm/include/cfullscreenwindow.hxx
+++ b/NxWidgets/nxwm/include/cfullscreenwindow.hxx
@@ -126,9 +126,11 @@ namespace NxWM
     /**
      * Block further activity on this window in preparation for window
      * shutdown.
+     *
+     * @param app. The application to be blocked
      */
 
-    void block(void);
+    void block(IApplication *app);
 
     /**
      * Set the window label
diff --git a/NxWidgets/nxwm/include/cwindowmessenger.hxx b/NxWidgets/nxwm/include/cwindowmessenger.hxx
index 645e750cb1..0aa8961bb8 100644
--- a/NxWidgets/nxwm/include/cwindowmessenger.hxx
+++ b/NxWidgets/nxwm/include/cwindowmessenger.hxx
@@ -98,6 +98,14 @@ namespace NxWM
     void handleKeyboardEvent(void);
 #endif
 
+    /**
+     * Handle a NX window blocked event
+     *
+     * @param arg - User provided argument (see nx_block or nxtk_block)
+     */
+ 
+    void handleBlockedEvent(FAR void *arg);
+
   public:
 
     /**
@@ -111,16 +119,6 @@ namespace NxWM
      */
 
     ~CWindowMessenger(void);
-
-    /**
-     * Destroy the application window and everything in it.  This is
-     * handled by CWindowMessenger (vs just calling the destructors) because
-     * in the case where an application destroys itself (because of pressing
-     * the stop button), then we need to unwind and get out of the application
-     * logic before destroying all of its objects.
-     */
-
-    void destroy(IApplication *app);
   };
 }
 #endif // __cplusplus
diff --git a/NxWidgets/nxwm/include/iapplication.hxx b/NxWidgets/nxwm/include/iapplication.hxx
index 28e50e0136..456202c6d4 100644
--- a/NxWidgets/nxwm/include/iapplication.hxx
+++ b/NxWidgets/nxwm/include/iapplication.hxx
@@ -45,8 +45,6 @@
 #include "cnxstring.hxx"
 #include "ibitmap.hxx"
 
-#include "iapplicationwindow.hxx"
-
 /****************************************************************************
  * Pre-Processor Definitions
  ****************************************************************************/
@@ -60,6 +58,12 @@
 namespace NxWM
 {
   /**
+   * Foward references
+   */
+
+  class IApplicationWindow;
+
+  /**
    * IApplication provides the abstract base class for each NxWM application.
    */
 
diff --git a/NxWidgets/nxwm/include/iapplicationwindow.hxx b/NxWidgets/nxwm/include/iapplicationwindow.hxx
index ed221797d4..60f1b332c6 100644
--- a/NxWidgets/nxwm/include/iapplicationwindow.hxx
+++ b/NxWidgets/nxwm/include/iapplicationwindow.hxx
@@ -46,6 +46,8 @@
 #include "cnxstring.hxx"
 #include "cwidgetcontrol.hxx"
 
+#include "iapplication.hxx"
+
 /****************************************************************************
  * Pre-Processor Definitions
  ****************************************************************************/
@@ -59,6 +61,12 @@
 namespace NxWM
 {
   /**
+   * Foward references
+   */
+
+  class IApplication;
+
+  /**
    * This callback class is used by the application to get notification of toolbar
    * related events.
    */
@@ -137,9 +145,11 @@ namespace NxWM
     /**
      * Block further activity on this window in preparation for window
      * shutdown.
+     *
+     * @param app. The application to be blocked
      */
 
-    virtual void block(void) = 0;
+    virtual void block(IApplication *app) = 0;
 
     /**
      * Set the window label
diff --git a/NxWidgets/nxwm/src/capplicationwindow.cxx b/NxWidgets/nxwm/src/capplicationwindow.cxx
index c0bc9ed62c..5cf172ea62 100644
--- a/NxWidgets/nxwm/src/capplicationwindow.cxx
+++ b/NxWidgets/nxwm/src/capplicationwindow.cxx
@@ -426,9 +426,11 @@ NXWidgets::CWidgetControl *CApplicationWindow::getWidgetControl(void) const
 /**
  * Block further activity on this window in preparation for window
  * shutdown.
+ *
+ * @param app. The application to be blocked
  */
 
-void CApplicationWindow::block(void)
+void CApplicationWindow::block(IApplication *app)
 {
   // Get the widget control from the NXWidgets::CNxWindow instance
 
@@ -437,7 +439,7 @@ void CApplicationWindow::block(void)
   // And then block further reporting activity on the underlying
   // NX framed window
 
-  nxtk_block(control->getWindowHandle());
+  nxtk_block(control->getWindowHandle(), (FAR void *)app);
 }
 
 /**
diff --git a/NxWidgets/nxwm/src/ccalibration.cxx b/NxWidgets/nxwm/src/ccalibration.cxx
index d93f56a47a..6f5976100b 100644
--- a/NxWidgets/nxwm/src/ccalibration.cxx
+++ b/NxWidgets/nxwm/src/ccalibration.cxx
@@ -220,13 +220,13 @@ void CCalibration::stop(void)
 
 void CCalibration::destroy(void)
 {
-  // Block any further window messages
+  // Make sure that the application is stopped (should already be stopped)
 
-  m_window->block();
+  stop();
 
-  // Make sure that the application is stopped
+  // Block any further window messages
 
-  stop();
+  m_window->block(this);
 }
 
 /**
diff --git a/NxWidgets/nxwm/src/cfullscreenwindow.cxx b/NxWidgets/nxwm/src/cfullscreenwindow.cxx
index 0c34166c06..6ec5bf802d 100644
--- a/NxWidgets/nxwm/src/cfullscreenwindow.cxx
+++ b/NxWidgets/nxwm/src/cfullscreenwindow.cxx
@@ -36,7 +36,7 @@
 /********************************************************************************************
  * Included Files
  ********************************************************************************************/
- 
+
 #include <nuttx/config.h>
 
 #include <nuttx/nx/nxglib.h>
@@ -141,9 +141,11 @@ NXWidgets::CWidgetControl *CFullScreenWindow::getWidgetControl(void) const
 /**
  * Block further activity on this window in preparation for window
  * shutdown.
+ *
+ * @param app. The application to be blocked
  */
 
-void CFullScreenWindow::block(void)
+void CFullScreenWindow::block(IApplication *app)
 {
   // Get the widget control from the NXWidgets::CNxWindow instance
 
@@ -152,7 +154,7 @@ void CFullScreenWindow::block(void)
   // And then block further reporting activity on the underlying
   // NX raw window
 
-  nx_block(control->getWindowHandle());
+  nx_block(control->getWindowHandle(), (FAR void *)app);
 }
 
 /**
diff --git a/NxWidgets/nxwm/src/cnxconsole.cxx b/NxWidgets/nxwm/src/cnxconsole.cxx
index 64321ddfbf..6a64afc1be 100644
--- a/NxWidgets/nxwm/src/cnxconsole.cxx
+++ b/NxWidgets/nxwm/src/cnxconsole.cxx
@@ -341,7 +341,7 @@ void CNxConsole::destroy(void)
 {
   // Block any further window messages
 
-  m_window->block();
+  m_window->block(this);
 
   // Make sure that the application is stopped
 
diff --git a/NxWidgets/nxwm/src/cstartwindow.cxx b/NxWidgets/nxwm/src/cstartwindow.cxx
index 3dfab50975..af46e7b826 100644
--- a/NxWidgets/nxwm/src/cstartwindow.cxx
+++ b/NxWidgets/nxwm/src/cstartwindow.cxx
@@ -234,7 +234,7 @@ void CStartWindow::destroy(void)
 
   // Block any further window messages
 
-  m_window->block();
+  m_window->block(this);
 
   // Make sure that the application is stopped
 
diff --git a/NxWidgets/nxwm/src/cwindowmessenger.cxx b/NxWidgets/nxwm/src/cwindowmessenger.cxx
index 4e458566d3..b467f533cf 100644
--- a/NxWidgets/nxwm/src/cwindowmessenger.cxx
+++ b/NxWidgets/nxwm/src/cwindowmessenger.cxx
@@ -91,31 +91,6 @@ CWindowMessenger::~CWindowMessenger(void)
 }
 
 /**
- * Destroy the application window and everything in it.  This is
- * handled by CWindowMessenger (vs just calling the destructors) because
- * in the case where an application destroys itself (because of pressing
- * the stop button), then we need to unwind and get out of the application
- * logic before destroying all of its objects.
- */
-
-void CWindowMessenger::destroy(IApplication *app)
-{
-  // Send a message to destroy the window isntance at a later time
-
-  struct SStartWindowMessage outmsg;
-  outmsg.msgId    = MSGID_DESTROY_APP;
-  outmsg.instance = (FAR void *)app;
-
-  gdbg("Sending MSGID_DESTROY_APP with instance=%p\n", app);
-  int ret = mq_send(m_mqd, &outmsg, sizeof(struct SStartWindowMessage),
-                    CONFIG_NXWM_STARTWINDOW_MXMPRIO);
-  if (ret < 0)
-    {
-      gdbg("ERROR: mq_send failed: %d\n", errno);
-    }
-}
-
-/**
  * Handle an NX window mouse input event.
  *
  * @param e The event data.
@@ -208,3 +183,35 @@ void CWindowMessenger::handleKeyboardEvent(void)
     }
 }
 #endif
+
+/**
+ * Handle a NX window blocked event.  This handler is called when we
+ * receive the BLOCKED message meaning that there are no further pending
+ * actions on the window.  It is now safe to delete the window.
+ *
+ * This is handled by sending a message to the start window thread (vs just
+ * calling the destructors) because in the case where an application
+ * destroys itself (because of pressing the stop button), then we need to
+ * unwind and get out of the application logic before destroying all of its
+ * objects.
+ *
+ * @param arg - User provided argument (see nx_block or nxtk_block)
+ */
+
+void CWindowMessenger::handleBlockedEvent(FAR void *arg)
+{
+  // Send a message to destroy the window isntance at a later time
+
+  struct SStartWindowMessage outmsg;
+  outmsg.msgId    = MSGID_DESTROY_APP;
+  outmsg.instance = arg;
+
+  gdbg("Sending MSGID_DESTROY_APP with instance=%p\n", arg);
+  int ret = mq_send(m_mqd, &outmsg, sizeof(struct SStartWindowMessage),
+                    CONFIG_NXWM_STARTWINDOW_MXMPRIO);
+  if (ret < 0)
+    {
+      gdbg("ERROR: mq_send failed: %d\n", errno);
+    }
+}
+
diff --git a/nuttx/graphics/nxmu/nx_block.c b/nuttx/graphics/nxmu/nx_block.c
index 10dad8b94a..2f069f0962 100644
--- a/nuttx/graphics/nxmu/nx_block.c
+++ b/nuttx/graphics/nxmu/nx_block.c
@@ -94,13 +94,15 @@
  *
  * Input Parameters:
  *   wnd - The window to be blocked
+ *   arg - An argument that will accompany the block messages (This is arg2
+ *         in the blocked callback).
  *
  * Return:
  *   OK on success; ERROR on failure with errno set appropriately
  *
  ****************************************************************************/
 
-int nx_block(NXWINDOW hwnd)
+int nx_block(NXWINDOW hwnd, FAR void *arg)
 {
   FAR struct nxbe_window_s *wnd = (FAR struct nxbe_window_s *)hwnd;
   struct nxsvrmsg_blocked_s outmsg;
@@ -132,6 +134,7 @@ int nx_block(NXWINDOW hwnd)
 
       outmsg.msgid = NX_SVRMSG_BLOCKED;
       outmsg.wnd   = wnd;
+      outmsg.arg   = arg;
 
       /* Send the window message via nxmu_sendserver (vs. nxmu_sendwindow) so
        * that it will not be blocked.
diff --git a/nuttx/graphics/nxmu/nx_eventhandler.c b/nuttx/graphics/nxmu/nx_eventhandler.c
index 75300b2481..944bb12d11 100644
--- a/nuttx/graphics/nxmu/nx_eventhandler.c
+++ b/nuttx/graphics/nxmu/nx_eventhandler.c
@@ -245,7 +245,7 @@ int nx_eventhandler(NXHANDLE handle)
         DEBUGASSERT(wnd);
         if (wnd->cb->blocked)
           {
-            wnd->cb->blocked((NXWINDOW)wnd, wnd->arg);
+            wnd->cb->blocked((NXWINDOW)wnd, wnd->arg, blocked->arg);
           }
         }
       break;
diff --git a/nuttx/graphics/nxmu/nxfe.h b/nuttx/graphics/nxmu/nxfe.h
index a70e635f58..8b6a21ef48 100644
--- a/nuttx/graphics/nxmu/nxfe.h
+++ b/nuttx/graphics/nxmu/nxfe.h
@@ -258,6 +258,7 @@ struct nxclimsg_blocked_s
 {
   uint32_t msgid;                /* NX_CLIMSG_BLOCKED */
   FAR struct nxbe_window_s *wnd; /* The window that is blocked */
+  FAR void *arg;                 /* User argument */
 };
 
 /* Client-to-Server Message Structures **************************************/
@@ -299,6 +300,7 @@ struct nxsvrmsg_blocked_s
 {
   uint32_t msgid;                /* NX_SVRMSG_BLOCKED */
   FAR struct nxbe_window_s *wnd; /* The window that is blocked */
+  FAR void *arg;                 /* User argument */
 };
 
 /* This message requests the server to create a new window */
diff --git a/nuttx/graphics/nxmu/nxmu_server.c b/nuttx/graphics/nxmu/nxmu_server.c
index c412b14924..2730e0ea28 100644
--- a/nuttx/graphics/nxmu/nxmu_server.c
+++ b/nuttx/graphics/nxmu/nxmu_server.c
@@ -154,13 +154,14 @@ static inline void nxmu_shutdown(FAR struct nxfe_state_s *fe)
  * Name: nxmu_blocked
  ****************************************************************************/
 
-static inline void nxmu_blocked(FAR struct nxbe_window_s *wnd)
+static inline void nxmu_blocked(FAR struct nxbe_window_s *wnd, FAR void *arg)
 {
   struct nxclimsg_blocked_s outmsg;
   int ret;
 
   outmsg.msgid = NX_CLIMSG_BLOCKED;
   outmsg.wnd   = wnd;
+  outmsg.arg   = arg;
 
   ret = nxmu_sendclient(wnd->conn, &outmsg, sizeof(struct nxclimsg_blocked_s));
   if (ret < 0)
@@ -380,7 +381,7 @@ int nx_runinstance(FAR const char *mqname, FAR NX_DRIVERTYPE *dev)
          case NX_SVRMSG_BLOCKED: /* Block messsages to a window */
            {
              FAR struct nxsvrmsg_blocked_s *blocked = (FAR struct nxsvrmsg_blocked_s *)buffer;
-             nxmu_blocked(blocked->wnd);
+             nxmu_blocked(blocked->wnd, blocked->arg);
            }
            break;
 
diff --git a/nuttx/include/nuttx/nx/nx.h b/nuttx/include/nuttx/nx/nx.h
index 4a228de253..153c34a3e5 100644
--- a/nuttx/include/nuttx/nx/nx.h
+++ b/nuttx/include/nuttx/nx/nx.h
@@ -209,8 +209,9 @@ struct nx_callback_s
    *
    * Input Parameters:
    *   hwnd - Window handle of the blocked window
-   *   arg  - User provided argument (see nx_openwindow, nx_requestbkgd,
+   *   arg1 - User provided argument (see nx_openwindow, nx_requestbkgd,
    *          nxtk_openwindow, or nxtk_opentoolbar)
+   *   arg2 - User provided argument (see nx_block or nxtk_block)
    *
    * Returned Value:
    *   None
@@ -218,7 +219,7 @@ struct nx_callback_s
    **************************************************************************/
 
 #ifdef CONFIG_NX_MULTIUSER
-  void (*blocked)(NXWINDOW hwnd, FAR void *arg);
+  void (*blocked)(NXWINDOW hwnd, FAR void *arg1, FAR void *arg2);
 #endif
 };
 
@@ -487,6 +488,8 @@ EXTERN int nx_closewindow(NXWINDOW hwnd);
  *
  * Input Parameters:
  *   wnd - The window to be blocked
+ *   arg - An argument that will accompany the block messages (This is arg2
+ *         in the blocked callback).
  *
  * Return:
  *   OK on success; ERROR on failure with errno set appropriately
@@ -494,7 +497,7 @@ EXTERN int nx_closewindow(NXWINDOW hwnd);
  ****************************************************************************/
 
 #ifdef CONFIG_NX_MULTIUSER
-EXTERN int nx_block(NXWINDOW hwnd);
+EXTERN int nx_block(NXWINDOW hwnd, FAR void *arg);
 #endif
 
 /****************************************************************************
diff --git a/nuttx/include/nuttx/nx/nxtk.h b/nuttx/include/nuttx/nx/nxtk.h
index a69d177759..60080e47fc 100644
--- a/nuttx/include/nuttx/nx/nxtk.h
+++ b/nuttx/include/nuttx/nx/nxtk.h
@@ -173,6 +173,8 @@ EXTERN int nxtk_closewindow(NXTKWINDOW hfwnd);
  *
  * Input Parameters:
  *   hfwnd - The window to be blocked
+ *   arg - An argument that will accompany the block messages (This is arg2
+ *         in the blocked callback).
  *
  * Return:
  *   OK on success; ERROR on failure with errno set appropriately
@@ -180,7 +182,7 @@ EXTERN int nxtk_closewindow(NXTKWINDOW hfwnd);
  ****************************************************************************/
 
 #ifdef CONFIG_NX_MULTIUSER
-EXTERN int nxtk_block(NXTKWINDOW hfwnd);
+EXTERN int nxtk_block(NXTKWINDOW hfwnd, FAR void *arg);
 #endif
 
 /****************************************************************************