XdbeSwapBuffers - swaps front and back DBE buffers.
#include <X11/extensions/Xdbe.h>
Status XdbeSwapBuffers(
   Display *dpy,
   XdbeSwapInfo *swap_info,
   int num_windows)
This function swaps the front and back buffers for a list of windows. The
  argument num_windows specifies how many windows are to have their
  buffers swapped; it is the number of elements in the swap_info array.
  The argument swap_info specifies the information needed per window to
  do the swap.
The XdbeSwapInfo structure has the following fields:
   Window swap_window
   XdbeSwapAction swap_action
swap_window specifies the window for which to swap buffers.
    swap_action specifies the swap action to use for this
    swap_window.
swap_action determines what will happen to the new back
    buffer of the swap_window it is paired with in the list in addition
    to making the old back buffer become visible. The defined actions are as
    follows:
  - XdbeUndefined
- The contents of the new back buffer become undefined. This may be the most
      efficient action since it allows the implementation to discard the
      contents of the buffer if it needs to.
- XdbeBackground
- The unobscured region of the new back buffer will be tiled with the window
      background. The background action allows devices to use a fast clear
      capability during a swap.
- XdbeUntouched
- The unobscured region of the new back buffer will be unmodified by the
      swap.
- XdbeCopied
- The unobscured region of the new back buffer will be the contents of the
      old back buffer
  - BadMatch
- A non-double-buffered window was specified or a window was specified
      twice.
- BadWindow
- An invalid window was specified.
- BadValue
- An invalid swap action was specified.
DBE, XdbeAllocateBackBufferName(), XdbeBeginIdiom(),
  XdbeDeallocateBackBufferName(), XdbeEndIdiom(),
  XdbeFreeVisualInfo(), XdbeGetBackBufferAttributes(),
  XdbeGetVisualInfo(), XdbeQueryExtension().