fix SCM_STACK_OVERFLOW_P bug

[bpt/guile.git] / libguile / stackchk.h

diff --git a/libguile/stackchk.h b/libguile/stackchk.h
index 8681f5d..68dec76 100644 (file)
--- a/libguile/stackchk.h
+++ b/libguile/stackchk.h
@@ -3,21 +3,22 @@
 #ifndef SCM_STACKCHK_H
 #define SCM_STACKCHK_H
 
-/* Copyright (C) 1995,1996,1998,2000, 2003, 2006, 2008 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1998,2000, 2003, 2006, 2008, 2009, 2010 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 as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 3 of
+ * the License, or (at your option) any later version.
  *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
  */
 
 \f
@@ -33,15 +34,13 @@
  */
 #define SCM_STACK_CHECKING_P SCM_STACK_LIMIT
 
-#ifdef STACK_CHECKING
+#if defined BUILDING_LIBGUILE && defined STACK_CHECKING
 # if SCM_STACK_GROWS_UP
 #  define SCM_STACK_OVERFLOW_P(s)\
-   (SCM_STACK_PTR (s) \
-    > (SCM_I_CURRENT_THREAD->base + SCM_STACK_LIMIT))
+   ((SCM_STACK_PTR (s) - SCM_I_CURRENT_THREAD->base) > SCM_STACK_LIMIT)
 # else
 #  define SCM_STACK_OVERFLOW_P(s)\
-   (SCM_STACK_PTR (s) \
-    < (SCM_I_CURRENT_THREAD->base - SCM_STACK_LIMIT))
+   ((SCM_I_CURRENT_THREAD->base - SCM_STACK_PTR (s)) > SCM_STACK_LIMIT)
 # endif
 # define SCM_CHECK_STACK\
     {\
@@ -51,7 +50,7 @@
     }
 #else
 # define SCM_CHECK_STACK /**/
-#endif /* STACK_CHECKING */
+#endif
 
 SCM_API int scm_stack_checking_enabled_p;