diff --git pthread/knot_comb.c pthread/knot_comb.c
index ad59515..de401be 100644
--- pthread/knot_comb.c
+++ pthread/knot_comb.c
@@ -709,7 +709,7 @@ char *input_get_line(input_state *state )
         empty = & state->buf[state->valid];
         tmp = read(state->socket, (void *)empty, (unsigned int )(511 - state->valid));
         n = tmp;
-        if (n <= 0) {
+        if (n == 0) {
           result = (char *)((void *)0);
           done = 1;
         } else {