+
+PERLVAR(Isavebegin, bool) /* save BEGINs for compiler */
+
+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 */
+
+/* New variables must be added to the very end, before this comment,
+ * for binary compatibility (the offsets of the old members must not change).
+ * XSUB.h provides wrapper functions via perlapi.h that make this
+ * irrelevant, but not all code may be expected to #include XSUB.h. */
+