handle get_window_pointer(handle window, int index)
This function obtains a pointer in the window's extra memory at a given offset.
The handle of the window whose extra memory is being queried.
The index into the window's extra memory of the value to be queried.
The value at the specified offset or zero if an error occurred.
The index member may be one of the standard offsets documented in the enumeration offset or it may be an application defined value. The index must be a multiple of eight.
offsets applicable to dialogs may be found in enumeration dialog_offset.
Extra window memory may be reserved when registering a window class (see member window of window_class). When extra memory is reserved in this fashion, the resultant memory occurs at positive offsets (starting at zero). The index for accessing such memory may range from zero up to the number of bytes of extra memory minus 8. For example, if 16 bytes of extra memory have been reserved, valid values for the index are 0 and 8.