XConfigureWindow, XMoveWindow, XResizeWindow, XMoveResizeWindow, XSetWindowBorderWidth, XWindowChanges (3) - configure windows and window changes structure
XGetWindowAttributes, XGetGeometry, XWindowAttributes (3) - get current window attribute or geometry and current window attributes structure
XNextEvent, XPeekEvent, XWindowEvent, XCheckWindowEvent, XMaskEvent, XCheckMaskEvent, XCheckTypedEvent, XCheckTypedWindowEvent (3) - select events by type
xwininfo (1) - window information utility for X