C SPECIFICATION

       void glXSwapBuffers( Display *dpy,
                            GLXDrawable drawable )

PARAMETERS

       dpy       Specifies the connection to the X server.

       drawable  Specifies the drawable whose buffers are to be swapped.

DESCRIPTION

       glXSwapBuffers  promotes the contents of the back buffer of drawable to
       become the contents of the front buffer of drawable.  The  contents  of
       the  back  buffer  then  become  undefined.  The update typically takes
       place during the vertical retrace of the monitor, rather  than  immedi-
       ately after glXSwapBuffers is called.

       glXSwapBuffers  performs an implicit glFlush before it returns.  Subse-
       quent  OpenGL  commands  may  be  issued  immediately   after   calling
       glXSwapBuffers,  but are not executed until the buffer exchange is com-
       pleted.

       If drawable was not created with respect to a  double-buffered  visual,
       glXSwapBuffers has no effect, and no error is generated.

NOTES

       The  contents  of  the  back buffer become undefined after a swap. Note
       that this applies to pixel buffers as well as windows.

       All GLX rendering contexts share the same notion  of  which  are  front
       buffers  and which are back buffers.  One consequence is that when mul-
       tiple clients are rendering to the same double-buffered window, all  of
       them  should  finish rendering before one of them issues the command to
       swap buffers.  The clients are responsible for implementing  this  syn-
       chronization.  Typically this is accomplished by executing glFinish and
       then using a semaphore in shared memory to rendezvous before  swapping.

ERRORS

       GLXBadDrawable is generated if drawable is not a valid GLX drawable.

       GLXBadCurrentWindow  is  generated if dpy and drawable are respectively
       the display and drawable associated with the  current  context  of  the
       calling  thread,  and  drawable  identifies  a window that is no longer
       valid.

SEE ALSO

       glFlush



                                                            GLXSWAPBUFFERS(3G)