Always calculate the elapsed transfer time every time around the loop, even if not displaying anything; and take -W into account so the elapsed time doesn't start ticking up until the first byte or line transferred, even if not displaying anything - so that -Q will report the right thing when querying a "pv -n" (#101).

src/pv/loop.c

@@ -526,16 +526,6 @@ int pv_main_loop(pvstate_t state)
 			pv_nanosleep(50000000);
 		}
 
-		/*
-		 * Just go round the loop again if there's no display and
-		 * we're not reporting statistics.
-		 *
-		 * TODO: still calculate elapsed time, otherwise -Q can't
-		 * read it (#101).
-		 */
-		if (state->control.no_display && !state->control.show_stats)
-			continue;
-
 		/*
 		 * If -W was given, we don't output anything until we have
 		 * written a byte (or line, in line mode), at which point
@@ -577,6 +567,18 @@ int pv_main_loop(pvstate_t state)
 			pv_elapsedtime_add_nsec(&next_update, (long long) (1000000000.0 * state->control.interval));
 		}
 
+		/* Calculate the elapsed transfer time. */
+		state->transfer.elapsed_seconds =
+		    pv__elapsed_transfer_time(&start_time, &cur_time, &(state->signal.toffset));
+
+		/*
+		 * Just go round the loop again if there's no display and
+		 * we're not reporting statistics.
+		 */
+		if (state->control.no_display && !state->control.show_stats) {
+			continue;
+		}
+
 		/* Restart the loop if it's not time to update the display. */
 		if (pv_elapsedtime_compare(&cur_time, &next_update) < 0) {
 			continue;
@@ -588,10 +590,6 @@ int pv_main_loop(pvstate_t state)
 		if (pv_elapsedtime_compare(&next_update, &cur_time) < 0)
 			pv_elapsedtime_copy(&next_update, &cur_time);
 
-		/* Calculate the elapsed transfer time. */
-		state->transfer.elapsed_seconds =
-		    pv__elapsed_transfer_time(&start_time, &cur_time, &(state->signal.toffset));
-
 		/* Resize the display, if a resize signal was received. */
 		(void) pv__resize_display_on_signal(state);