SetClassWord

The SetClassWord function replaces the 16-bit (word) value at the specified offset into the extra class memory for the window class to which the specified window belongs.

The GCW_ values supported by 16-bit Windows are obsolete. You must use the SetClassLong function to set the class values previously set by using the GCW_ values with the SetClassWord function.

WORD SetClassWord(
  HWND hWnd,      // handle of window
  int nIndex,     // index of value to change
  WORD wNewWord   // new value
);
 

Parameters

hWnd

Handle to the window and, indirectly, the class to which the window belongs.

nIndex

Specifies the zero-based byte offset of the value to be replaced. 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 8 would be an index to the fifth 16-bit integer.

wNewWord

Specifies the replacement value.

Return Values

If the function succeeds, the return value is the previous value of the specified 16-bit integer. If the value was not previously set, the return value is zero.

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.

See Also

Window Classes Overview, Window Class Functions, GetClassWord, RegisterClass, SetClassLong, WNDCLASS