diff --git a/libc/stdio/fwalk.c b/libc/stdio/fwalk.c
index 5606cf1..b1df891 100644
--- a/libc/stdio/fwalk.c
+++ b/libc/stdio/fwalk.c
@@ -45,8 +45,9 @@
 
 	ret = 0;
 	for (g = &__sglue; g != NULL; g = g->next)
-		for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
-			if (fp->_flags != 0)
+		for (fp = g->iobs, n = g->niobs; --n >= 0; fp++) {
+			if ((fp->_flags != 0) && ((fp->_flags & __SIGN) == 0))
 				ret |= (*function)(fp);
+		}
 	return (ret);
 }