Message Function

The Wxutil.h header file in the Microsoft® DirectShow® base classes provides a helper function for processing messages.

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

WaitDispatchingMessages

Message Function

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

Syntax

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

Parameters

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

Return Value

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.

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.

Remarks

WaitDispatchingMessages enables windows to process sent messages while it waits for a handle to a window. Use this function to wait for a processing object and to perform mutually exclusive operations, avoiding possible deadlocks in objects with windows.
This helper function is similar to the Win32 WaitForSingleObject function.

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.