This function waits for a for the HANDLE hObject before dispatching messages. While waiting, messages sent to windows on the thread by SendMessage will be processed.

DWORD WINAPI WaitDispatchingMessages(
  HANDLE hObject,
  DWORD dwWait,
  HWND hwnd = NULL,
  UINT uMsg = 0


  • hObject
    Handle of object to wait for.
  • dwWait
    Time-out interval in milliseconds.
  • hwnd
    Handle to a window.
  • uMsg
    Win32 message.

Return Values

If the function succeeds, the return value indicates the event that caused the function to return. If the function fails, the return value is WAIT_FAILED.

The return value on success is one of the following values.

Value Description
WAIT_ABANDONED The specified object is a mutex (mutual exclusion) object that was not released by the thread that owned the mutex object before the owning thread terminated. Ownership of the mutex object is granted to the calling thread, and the mutex is set to nonsignaled.
WAIT_OBJECT_0 The state of the specified object is signaled.
WAIT_TIMEOUT The time-out interval elapsed, and the object's state is nonsignaled.


This function enables sent messages to be processed while waiting for a handle to a window. Use this function to wait for an object to be processed and to perform mutually exclusive operations, consequently avoiding possible deadlocks in objects with windows.

This helper function is similar to the Win32 WaitForSingleObject function.


DirectShow applications and DirectShow filters have different include file and link library requirements. See Setting Up the Build Environment for more information.

OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.

Last updated on Wednesday, April 13, 2005

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