How would you synchronize two webcams to be acquiring their images at the same times?

So does this mean that each grab obtains the latest image taken by the camera over the camera’s course of endlessly looping its initially set frame rate, and hence we wait a little in the common and almost certain case that it is still in the middle of completing its next image acquisition at the precise time that we grab it?

I mean unless we were timing our grabs so precisely aligned to the camera’s loop time that we never had to wait, which is obviously impractical.