+#if HAVE_SYSMP && defined MP_SAGET && defined MPSA_RMINFO && defined _SC_PAGESIZE
+ { /* This works on irix6. */
+ struct rminfo realmem;
+ if (sysmp(MP_SAGET, MPSA_RMINFO, &realmem, sizeof(realmem)) == 0)
+ {
+ double pagesize = sysconf (_SC_PAGESIZE);
+ double pages = realmem.availrmem;
+ if (0 <= pages && 0 <= pagesize)
+ return pages * pagesize;
+ }
+ }
+#endif
+
+#if HAVE_TABLE && HAVE_SYS_TABLE_H
+ { /* This works on Tru64 UNIX V4/5. */
+ struct tbl_vmstats vmstats;
+
+ if (table (TBL_VMSTATS, 0, &vmstats, 1, sizeof (vmstats)) == 1)
+ {
+ double pages = vmstats.free_count;
+ double pagesize = vmstats.pagesize;
+
+ if (0 <= pages && 0 <= pagesize)
+ return pages * pagesize;
+ }
+ }
+#endif
+