Definition of "guardroom"

There were flambeaux on staggering poles every ten strides or so, and at intervals of about a hundred strides, bartizans whose guardroom windows glared like fireworks clung to the bridge piers.

1980, Gene Wolfe, chapter XIV, in The Shadow of the Torturer (The Book of the New Sun; 1), New York: Simon & Schuster, pages 131–132