diff --git a/src/expect-core b/src/expect-core
index 29dbb45..50a18ff 100644
--- a/src/expect-core
+++ b/src/expect-core
@@ -22,6 +22,9 @@
 [ -z $__INC_EXPECT_CORE ] || return
 __INC_EXPECT_CORE=1
 
+# reserved for our uses
+exec 99<>/dev/null
+
 
 ##
 # Shorthand for bailing out on unrecognized clauses