When EOF on input and output is reached but the output pipe buffer is not empty, sleep for a short time before looping while waiting for the buffer to empty, to avoid a busy-wait (#164).

src/pv/loop.c

@@ -400,6 +400,17 @@ int pv_main_loop(pvstate_t state)
 			}
 		}
 
+		/*
+		 * If we've read everything and written everything, and the
+		 * output pipe buffer is NOT empty, then pause a short while
+		 * so we don't spin in a tight loop waiting for the output
+		 * buffer to empty (#164).
+		 */
+		if (eof_in && eof_out && state->transfer.written_but_not_consumed > 0) {
+			debug("%s", "EOF but bytes remain in output pipe - sleeping");
+			pv_nanosleep(50000000);
+		}
+
 		/*
 		 * Just go round the loop again if there's no display and
 		 * we're not reporting statistics.