+PERLVAR(Icustom_op_names, HV*) /* Names of user defined ops */
+PERLVAR(Icustom_op_descs, HV*) /* Descriptions of user defined ops */
+
+#ifdef PERLIO_LAYERS
+PERLVARI(Iperlio, PerlIO *,NULL)
+PERLVARI(Iknown_layers, PerlIO_list_t *,NULL)
+PERLVARI(Idef_layerlist, PerlIO_list_t *,NULL)
+#endif
+
+PERLVARI(Iencoding, SV*, Nullsv) /* character encoding */
+
+PERLVAR(Idebug_pad, struct perl_debug_pad) /* always needed because of the re extension */
+
+PERLVAR(Itaint_warn, bool) /* taint warns instead of dying */
+
+#ifdef PL_OP_SLAB_ALLOC
+PERLVAR(IOpPtr,I32 **)
+PERLVARI(IOpSpace,I32,0)
+PERLVAR(IOpSlab,I32 *)
+#endif
+
+PERLVAR(Iutf8locale, bool) /* utf8 locale detected */
+
+PERLVAR(Iutf8_idstart, SV *)
+PERLVAR(Iutf8_idcont, SV *)
+
+PERLVAR(Isort_RealCmp, SVCOMPARE_t)
+
+PERLVARI(Icheckav_save, AV*, Nullav) /* save CHECK{}s when compiling */
+
+PERLVARI(Iclocktick, long, 0) /* this many times() ticks in a second */
+
+PERLVARI(Iin_load_module, int, 0) /* to prevent recursions in PerlIO_find_layer */
+
+PERLVAR(Iunicode, U32) /* Unicode features: $ENV{PERL_UNICODE} or -C */
+
+PERLVAR(Isignals, U32) /* Using which pre-5.8 signals */
+
+PERLVAR(Istashcache, HV *) /* Cache to speed up S_method_common */
+
+PERLVAR(Ireentrant_retint, int) /* Integer return value from reentrant functions */
+
+/* Hooks to shared SVs and locks. */
+PERLVARI(Isharehook, share_proc_t, MEMBER_TO_FPTR(Perl_sv_nosharing))
+PERLVARI(Ilockhook, share_proc_t, MEMBER_TO_FPTR(Perl_sv_nolocking))
+PERLVARI(Iunlockhook, share_proc_t, MEMBER_TO_FPTR(Perl_sv_nounlocking))
+PERLVARI(Ithreadhook, thrhook_proc_t, MEMBER_TO_FPTR(Perl_nothreadhook))
+
+/* Force inclusion of both runops options */
+PERLVARI(Irunops_std, runops_proc_t, MEMBER_TO_FPTR(Perl_runops_standard))
+PERLVARI(Irunops_dbg, runops_proc_t, MEMBER_TO_FPTR(Perl_runops_debug))
+
+/* Stores the PPID */
+#ifdef THREADS_HAVE_PIDS
+PERLVARI(Ippid, IV, 0)
+#endif
+
+PERLVARI(Ihash_seed, UV, 0) /* Hash initializer */
+
+PERLVAR(IDBassertion, SV *)
+
+PERLVARI(Icv_has_eval, I32, 0) /* PL_compcv includes an entereval or similar */
+
+/* New variables must be added to the very end, before this comment,
+ * for binary compatibility (the offsets of the old members must not change).
+ * (Don't forget to add your variable also to perl_clone()!)