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This function retrieves information about the specified window. GetWindowLongalso retrieves the 32-bit (long) value at the specified offset into the extra window memory of a window.
A remote application interface (RAPI) version of this function exists, and it is called CeGetWindowLong.
LONG GetWindowLong( HWND hWnd , int nIndex );
Parameters
Value | Description |
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GWL_EXSTYLE | Retrieves the extended window styles. |
GWL_STYLE | Retrieves the window styles. |
GWL_WNDPROC | Retrieves the address of the window procedure, or a handle representing the address of the window procedure. You must use the CallWindowProcfunction to call the window procedure. |
GWL_ID | Not supported. |
GWL_USERDATA | Gets the 32-bit value associated with the window. Each window has a corresponding 32-bit value intended for use by the application that created the window. Windows CE versions 2.0 and later support this value, but Windows CE versions 1.0 and 1.01 do not. |
The following values are also available when the hWndparameter identifies a dialog box:
Value | Description |
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DWL_MSGRESULT | Retrieves the return value of a message processed in the dialog box procedure. |
DWL_USER | Retrieves extra information private to the application, such as handles or pointers. |
Return Values
The requested 32-bit value indicates success. Zero indicates failure. To get extended error information, call GetLastError.
Remarks
The nIndexparameter must be a multiple of 4 bytes.
Unaligned access is not supported.
Windows CE versions 1.0 and 1.01 also do not support the DWL_DLGPROC value in the nIndexparameter.
Requirements
Runs on | Versions | Defined in | Include | Link to |
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Windows CE OS | 1.0 and later | Winuser.h |
Note This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.
See Also
CallWindowProc, CeGetWindowLong, GetLastError, RegisterClass, SetParent, SetWindowLong, WNDCLASS