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#define INCL_WINWINDOWMGR
 
ULONG WinQueryWindowULong(hwnd, index)
HWND hwnd;      /* handle of the window       */
SHORT index;    /* index of value to retrieve */
 
The WinQueryWindowULong function retrieves an unsigned long integer value at
a specified offset into the reserved memory of a given window.
 
The window handle that is passed to this function can be the handle of a
window with the same or a different message queue from the caller; that is,
this function allows the caller to obtain data from windows belonging to
other threads.
 
Parameter  Description
────────────────────────────────────────────────────────────────────────────
 
hwnd       Identifies the window to query.
 
index      Specifies the zero-based index of the ULONG value to retrieve.
           Valid values are in the range zero through the number of bytes of
           window data (for example, a value of 8 would be an index to the
           third long integer), or any of the following QWL values:
 
           Value              Meaning
           ─────────────────────────────────────────────────────────────────
           QWL_HHEAP          Handle of the heap. This value only applies to
                              frame windows.
 
           QWL_HMQ            Handle of the message queue of the window.
 
           QWL_HWNDFOCUSSAVE  Handle of the window that last had the focus.
                              This value only applies to frame windows.
 
           QWL_STYLE          Window style.
 
           QWL_USER           ULONG value present in windows of the
                              following preregistered window classes:
 
                                   WC_DIALOG
                                   WC_FRAME
                                   WC_LISTBOX
                                   WC_BUTTON
                                   WC_STATIC
                                   WC_ENTRYFIELD
                                   WC_SCROLLBAR
                                   WC_MENU
 
           This value can be used to retrieve application-specific data in
           controls.
 
Return Value
 
The return value is the specified ULONG value in the window's reserved
memory.
 
Comments
 
The specified index is valid only if all the bytes referenced are within the
reserved memory. For example, this function would fail if an index value of
zero was specified and only two bytes had been reserved.
 
See Also
 
WinQueryWindowUShort, WinRegisterClass, WinSetWindowULong
 
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