GetClassWord function
Retrieves the 16-bit (WORD) value at the specified offset into the extra class memory for the window class to which the specified window belongs.
Syntax
WORD WINAPI GetClassWord(
_In_ HWND hWnd,
_In_ int nIndex
);
Parameters
- hWnd [in]
-
Type: HWND
A handle to the window and, indirectly, the class to which the window belongs.
- nIndex [in]
-
Type: int
The zero-based byte offset of the value to be retrieved. Valid values are in the range zero through the number of bytes of class memory, minus two; for example, if you specified 10 or more bytes of extra class memory, a value of eight would be an index to the fifth 16-bit integer. There is an additional valid value as shown in the following table.
Value Meaning - GCW_ATOM
- -32
Retrieves an ATOM value that uniquely identifies the window class. This is the same atom that the RegisterClass or RegisterClassEx function returns.
Return value
Type: Type: WORD
If the function succeeds, the return value is the requested 16-bit value.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
Remarks
Reserve extra class memory by specifying a nonzero value in the cbClsExtra member of the WNDCLASS structure used with the RegisterClass function.
Requirements
|
Minimum supported client |
Windows 2000 Professional [desktop apps only] |
|---|---|
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Minimum supported server |
Windows 2000 Server [desktop apps only] |
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Header |
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Library |
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DLL |
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See also
- Reference
- GetClassLong
- RegisterClass
- RegisterClassEx
- SetClassWord
- WNDCLASS
- Conceptual
- Window Classes