1 files changed, 1 insertions, 1 deletions
diff --git a/lib/fs.c b/lib/fs.c
index 5266ce9..e00f7fa 100644
--- a/lib/fs.c
+++ b/lib/fs.c
@@ -838,7 +838,7 @@ uc_fs_isatty(uc_vm_t *vm, size_t nargs)
 	if (fd == -1)
 		err_return(errno);
 
-	return ucv_boolean_new(isatty(fd));
+	return ucv_boolean_new(isatty(fd) == 1);
 }
 
 /**