WinSetWindowULong Parameter - index

index (LONG) - input

Zero-based index of the value to be set.

The units of index are bytes. Valid values are zero through (cbWindowData -4), where cbWindowData is the parameter in WinRegisterClass that specifies the number of bytes available for application-defined storage. Any of the QWL_* values are also valid.

Note: QWS_* values cannot be used.

QWL_DEFBUTTON

The default push button for a dialog.

The default push button is the one that sends its WM_COMMAND message when the enter key is pressed.

QWL_HMQ
Handle of message queue of window. Note that the leading 16 bits of this value are zero.
QWL_HWNDFOCUSSAVE
Window handle of the child windows of this window that last possessed the focus when this frame window was last deactivated.
QWL_PENDATA
Reserved for use by operating system extensions. It allows an operating system extension to store data on a per window basis.
QWL_STYLE
Window style.
QWL_USER
A ULONG value for applications to use is present at offset QWL_USER in windows of the following preregistered window classes:

WC_BUTTON
WC_COMBOBOX
WC_CONTAINER
WC_ENTRYFIELD
WC_FRAME (includes dialog windows)
WC_LISTBOX
WC_MENU
WC_MLE
WC_NOTEBOOK
WC_SCROLLBAR
WC_SLIDER
WC_SPINBUTTON
WC_STATIC
WC_TITTLEBAR
WC_VALUESET

This value can be used to place application-specific data in controls.
Other
Zero-based index.

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