NAME
	  glFlush - force execution of GL commands in finite time


     C SPECIFICATION
	  void glFlush(	void )


     DESCRIPTION
	  Different GL implementations buffer commands in several
	  different locations, including network buffers and the
	  graphics accelerator itself.	glFlush	empties	all of these
	  buffers, causing all issued commands to be executed as
	  quickly as they are accepted by the actual rendering engine.
	  Though this execution	may not	be completed in	any particular
	  time period, it does complete	in finite time.

	  Because any GL program might be executed over	a network, or
	  on an	accelerator that buffers commands, all programs	should
	  call glFlush whenever	they count on having all of their
	  previously issued commands completed.	 For example, call
	  glFlush before waiting for user input	that depends on	the
	  generated image.

     NOTES
	  glFlush can return at	any time.  It does not wait until the
	  execution of all previously issued GL	commands is complete.

     ERRORS
	  GL_INVALID_OPERATION is generated if glFlush is executed
	  between the execution	of glBegin and the corresponding
	  execution of glEnd.

     SEE ALSO
	  glFinish