1 files changed, 1 insertions, 1 deletions

diff --git a/shell/lash.c b/shell/lash.c
index d2d4298fb..e20c2a20e 100644
--- a/shell/lash.c
+++ b/shell/lash.c
@@ -1668,7 +1668,7 @@ int lash_main(int argc_l, char **argv_l)
          *    standard output is a terminal
          *    Refer to Posix.2, the description of the `sh' utility. */
         if (argv[optind]==NULL && input==stdin &&
-                        isatty(fileno(stdin)) && isatty(fileno(stdout))) {
+                        isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
                 interactive=TRUE;
         }
         setup_job_control();