GetQueueStatus function (winuser.h)

Article
10/13/2021
2 minutes to read

Retrieves the type of messages found in the calling thread's message queue.

Syntax

DWORD GetQueueStatus(
  [in] UINT flags
);

Parameters

[in] flags

Type: UINT

The types of messages for which to check. This parameter can be one or more of the following values.

Value	Meaning
QS_ALLEVENTS (QS_INPUT \| QS_POSTMESSAGE \| QS_TIMER \| QS_PAINT \| QS_HOTKEY)	An input, WM_TIMER, WM_PAINT, WM_HOTKEY, or posted message is in the queue.
QS_ALLINPUT (QS_INPUT \| QS_POSTMESSAGE \| QS_TIMER \| QS_PAINT \| QS_HOTKEY \| QS_SENDMESSAGE)	Any message is in the queue.
QS_ALLPOSTMESSAGE 0x0100	A posted message (other than those listed here) is in the queue.
QS_HOTKEY 0x0080	A WM_HOTKEY message is in the queue.
QS_INPUT (QS_MOUSE \| QS_KEY \| QS_RAWINPUT)	An input message is in the queue.
QS_KEY 0x0001	A WM_KEYUP, WM_KEYDOWN, WM_SYSKEYUP, or WM_SYSKEYDOWN message is in the queue.
QS_MOUSE (QS_MOUSEMOVE \| QS_MOUSEBUTTON)	A WM_MOUSEMOVE message or mouse-button message (WM_LBUTTONUP, WM_RBUTTONDOWN, and so on).
QS_MOUSEBUTTON 0x0004	A mouse-button message (WM_LBUTTONUP, WM_RBUTTONDOWN, and so on).
QS_MOUSEMOVE 0x0002	A WM_MOUSEMOVE message is in the queue.
QS_PAINT 0x0020	A WM_PAINT message is in the queue.
QS_POSTMESSAGE 0x0008	A posted message (other than those listed here) is in the queue.
QS_RAWINPUT 0x0400	A raw input message is in the queue. For more information, see Raw Input. Windows 2000: This flag is not supported.
QS_SENDMESSAGE 0x0040	A message sent by another thread or application is in the queue.
QS_TIMER 0x0010	A WM_TIMER message is in the queue.

Return value

Type: DWORD

The high-order word of the return value indicates the types of messages currently in the queue. The low-order word indicates the types of messages that have been added to the queue and that are still in the queue since the last call to the GetQueueStatus, GetMessage, or PeekMessage function.

Remarks

The presence of a QS_ flag in the return value does not guarantee that a subsequent call to the GetMessage or PeekMessage function will return a message. GetMessage and PeekMessage perform some internal filtering that may cause the message to be processed internally. For this reason, the return value from GetQueueStatus should be considered only a hint as to whether GetMessage or PeekMessage should be called.

The QS_ALLPOSTMESSAGE and QS_POSTMESSAGE flags differ in when they are cleared. QS_POSTMESSAGE is cleared when you call GetMessage or PeekMessage, whether or not you are filtering messages. QS_ALLPOSTMESSAGE is cleared when you call GetMessage or PeekMessage without filtering messages (wMsgFilterMin and wMsgFilterMax are 0). This can be useful when you call PeekMessage multiple times to get messages in different ranges.

Requirements


Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	winuser.h (include Windows.h)
Library	User32.lib
DLL	User32.dll
API set	ext-ms-win-ntuser-message-l1-1-0 (introduced in Windows 8)