Flushing the pipeline

[Andre T. Yew]

	My apologies if this has been discussed here before.  I'm recording 
some images right now off a 4D/240GTX, and I seem to be having some trouble
getting the IRIS to draw and output the image quickly enough.  That is, my
routine looks somewhat like this:  draw_frame(); 
				   prepare_VCR();  /* Tell VCR to sync frame */
				   record_frame();  
	Since this machine has lots of batch jobs running on it all the time,
performance is not optimal, and consequently draw_frame() goes slowly.  
However, since I call all of my functions sequentially, however slow the 
machine is, the program should draw the frame and then call prepare_VCR() and
record_frame() to record the new image.  Unfortunately, this is not the case. 
Sometimes, draw_frame() is called, but does not output the image in time to
record, so I get the previous frame instead of the one I want. 
	How do I make sure the pipeline is flushed before I sync the VCR and
record a frame?  Please respond by email, and I will summarize to the net if
there is sufficient interest.
						
						Thank you,
						Andre Yew
						andrey at through.cs.caltech.edu
						       (131.215.128.1)