--- freem/src/shmmgr.h	2025/01/19 02:04:04	1.1.1.1
+++ freem/src/shmmgr.h	2025/05/08 16:29:18	1.5
@@ -1,23 +1,11 @@
 /*
- *                            *
- *                           * *
- *                          *   *
- *                     ***************
- *                      * *       * *
- *                       *  MUMPS  *
- *                      * *       * *
- *                     ***************
- *                          *   *
- *                           * *
- *                            *
- *
- *   shmmgr.h
+ *   $Id: shmmgr.h,v 1.5 2025/05/08 16:29:18 snw Exp $
  *    shared memory manager data structures
  *
  *  
- *   Author: Serena Willis <jpw@coherent-logic.com>
+ *   Author: Serena Willis <snw@coherent-logic.com>
  *    Copyright (C) 1998 MUG Deutschland
- *    Copyright (C) 2021 Coherent Logic Development LLC
+ *    Copyright (C) 2021, 2025 Coherent Logic Development LLC
  *
  *
  *   This file is part of FreeM.
@@ -35,6 +23,19 @@
  *   You should have received a copy of the GNU Affero Public License
  *   along with FreeM.  If not, see <https://www.gnu.org/licenses/>.
  *
+ *   $Log: shmmgr.h,v $
+ *   Revision 1.5  2025/05/08 16:29:18  snw
+ *   Add SOM/SOA/SBM/SBA macros from RSM and modify for FreeM
+ *
+ *   Revision 1.4  2025/03/26 15:17:12  snw
+ *   Fall back to global-backed SSVNs when memory-backed globals fail in attempt to fix Tru64
+ *
+ *   Revision 1.3  2025/03/09 19:50:47  snw
+ *   Second phase of REUSE compliance and header reformat
+ *
+ *
+ * SPDX-FileCopyrightText:  (C) 2025 Coherent Logic Development LLC
+ * SPDX-License-Identifier: AGPL-3.0-or-later
  **/
 
 #if !defined(__shmmgr_h)
@@ -71,6 +72,15 @@
 
 #define SHMALIGN(a) (void *) (((unsigned long) a + sysconf (_SC_PAGESIZE)) & ~(sysconf (_SC_PAGESIZE) - 1))
 
+/* The following macros were borrowed from Reference Standard M
+ *  SOM/SOA:  reading and writing data stored in shared memory
+ *  SBM/SBA:  for modifying pointers in shared memory
+ */
+#define SOM(ptr)    ((__typeof__(ptr)) ((char *) (ptr) + ((char *) shm_config->dta - (char *) shm_config->hdr->shmad)))
+#define SOA(ptr)    ((ptr == NULL) ? NULL : SOM(ptr))
+#define SBM(ptr)    ((__typeof__(ptr)) ((char *) (ptr) - ((char *) shm_config->dta - (char *) shm_config->hdr->shmad)))
+#define SBA(ptr)    ((ptr == NULL) ? NULL : SBM(ptr))
+
 /* data structures */
 
 /* alloc map entry */
@@ -123,6 +133,7 @@ typedef struct shm_hdr_t {
     char *argptr;
     long PSIZE;
     long symlen;
+    short use_mb_globals;
     
     /* pid of process currently in transaction */
     /* zero if nobody owns these exclusive rights */