summaryrefslogtreecommitdiff
path: root/libguile/pairs.c
diff options
context:
space:
mode:
Diffstat (limited to 'libguile/pairs.c')
-rw-r--r--libguile/pairs.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/libguile/pairs.c b/libguile/pairs.c
index aaaeb110f..fb8b21f11 100644
--- a/libguile/pairs.c
+++ b/libguile/pairs.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1995,1996,2000,2001, 2004, 2005, 2006, 2008 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,2000,2001, 2004, 2005, 2006, 2008, 2009 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
@@ -27,11 +27,25 @@
#include "libguile/pairs.h"
+#include "verify.h"
+
/* {Pairs}
*/
+/*
+ * This compile-time test verifies the properties needed for the
+ * efficient test macro scm_is_null_or_nil defined in pairs.h,
+ * which is defined in terms of the SCM_MATCHES_BITS_IN_COMMON macro.
+ *
+ * See the comments preceeding the definitions of SCM_BOOL_F and
+ * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
+ */
+verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
+ (SCM_ELISP_NIL, SCM_EOL));
+
+
#if (SCM_DEBUG_PAIR_ACCESSES == 1)
#include "libguile/ports.h"