diff --git a/src/cmp/cmpcbk.lsp b/src/cmp/cmpcbk.lsp
index 63e789df4..ad2f29bb1 100644
--- a/src/cmp/cmpcbk.lsp
+++ b/src/cmp/cmpcbk.lsp
@@ -98,6 +98,7 @@
     (wt-nl1 "{")
     (when return-p
       (wt-nl return-type-name " output;"))
+    (wt-nl "const cl_env_ptr cl_env_copy = ecl_process_env();")
     (wt-nl "cl_object aux;")
     (wt-nl "ECL_BUILD_STACK_FRAME(cl_env_copy, frame, helper)")
     (loop for n from 0