LONG SetWindowLongW ( HWND hwnd, INT offset, LONG newval )
|hwnd||[In]||window to alter.|
|offset||[In]||offset,in bytes,of location to alter.|
|[In]||new value of location.|
SetWindowLongW (USER32.@) Set window attribute.
SetWindowLong alters one of a window's attributes or sets a 32-bit (long) value in a window's extra memory.
The _hwnd_ parameter specifies the handle to a window that has extra memory. The _newval_ parameter contains the new attribute or extra memory value. If positive, the _offset_ parameter is the byte-addressed location in the window's extra memory to set. If negative, _offset_ specifies the window attribute to set, and should be one of the following values:
GWL_EXSTYLE The window's extended window style.
GWL_STYLE The window's window style.
GWLP_WNDPROC Pointer to the window's window procedure.
GWLP_HINSTANCE The window's application instance handle.
GWLP_ID The window's identifier.
GWLP_USERDATA The window's user-specified data.
If the window is a dialog box, the _offset_ parameter can be one of the following values:
DWLP_DLGPROC The address of the window's dialog box procedure.
DWLP_MSGRESULT The return value of a message that the dialog box procedure processed.
DWLP_USER Application specific information.
If successful, returns the previous value located at _offset_. Otherwise, returns 0.
Extra memory for a window class is specified by a nonzero cbWndExtra parameter of the WNDCLASS structure passed to RegisterClass at the time of class creation.
Using GWL_WNDPROC to set a new window procedure effectively creates a window subclass. Use CallWindowProc in the new Windows® procedure to pass messages to the superclass's window procedure.
The user data is reserved for use by the application which created the window.
Do not use GWL_STYLE to change the window's WS_DISABLED style; instead, call the EnableWindow function to change the window's disabled state.
Do not use GWL_HWNDPARENT to reset the window's parent, use SetParent instead.
Win95: When offset is GWL_STYLE and the calling app's ver is 4.0, it sends WM_STYLECHANGING before changing the settings and WM_STYLECHANGED afterwards. App ver 4.0 can't use SetWindowLong to change WS_EX_TOPMOST.
Declared in "winuser.h". https://source.winehq.org/source/include/winuser.h
Implemented in "dlls/user32/win.c". https://source.winehq.org/source/dlls/user32/win.c
Debug channel "win".
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