From: Vincent Pit <perl@profvince.com>
Date: Wed, 4 Nov 2015 13:34:25 +0000 (-0200)
Subject: The Big Boilerplate Factorization
X-Git-Tag: rt117081~3
X-Git-Url: http://git.vpit.fr/?p=perl%2Fmodules%2FVariable-Magic.git;a=commitdiff_plain;h=d0d2f5ac7d4406b6158a57cddde7535285703c5e

The Big Boilerplate Factorization
---

diff --git a/MANIFEST b/MANIFEST
index c052756..3a657b9 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -48,3 +48,6 @@ t/lib/Variable/Magic/TestGlobalDestruction.pm
 t/lib/Variable/Magic/TestScopeEnd.pm
 t/lib/Variable/Magic/TestValue.pm
 t/lib/Variable/Magic/TestWatcher.pm
+xsh/caps.h
+xsh/threads.h
+xsh/util.h
diff --git a/Magic.xs b/Magic.xs
index 483431e..116eb8a 100644
--- a/Magic.xs
+++ b/Magic.xs
@@ -10,158 +10,30 @@
 #include "perl.h"
 #include "XSUB.h"
 
-#define __PACKAGE__ "Variable::Magic"
+/* --- XS helpers ---------------------------------------------------------- */
 
-#undef VOID2
-#ifdef __cplusplus
-# define VOID2(T, P) static_cast<T>(P)
-#else
-# define VOID2(T, P) (P)
-#endif
-
-#ifndef VMG_PERL_PATCHLEVEL
-# ifdef PERL_PATCHNUM
-#  define VMG_PERL_PATCHLEVEL PERL_PATCHNUM
-# else
-#  define VMG_PERL_PATCHLEVEL 0
-# endif
-#endif
-
-#define VMG_HAS_PERL(R, V, S) (PERL_REVISION > (R) || (PERL_REVISION == (R) && (PERL_VERSION > (V) || (PERL_VERSION == (V) && (PERL_SUBVERSION >= (S))))))
-
-#define VMG_HAS_PERL_BRANCH(R, V, S) (PERL_REVISION == (R) && PERL_VERSION == (V) && PERL_SUBVERSION >= (S))
-
-#define VMG_HAS_PERL_MAINT(R, V, S, P) (PERL_REVISION == (R) && PERL_VERSION == (V) && (VMG_PERL_PATCHLEVEL >= (P) || (!VMG_PERL_PATCHLEVEL && PERL_SUBVERSION >= (S))))
-
-/* --- Threads and multiplicity -------------------------------------------- */
-
-#ifndef NOOP
-# define NOOP
-#endif
-
-#ifndef dNOOP
-# define dNOOP
-#endif
-
-/* Safe unless stated otherwise in Makefile.PL */
-#ifndef VMG_FORKSAFE
-# define VMG_FORKSAFE 1
-#endif
-
-#ifndef VMG_MULTIPLICITY
-# if defined(MULTIPLICITY)
-#  define VMG_MULTIPLICITY 1
-# else
-#  define VMG_MULTIPLICITY 0
-# endif
-#endif
-#if VMG_MULTIPLICITY
-# ifndef PERL_IMPLICIT_CONTEXT
-#  error MULTIPLICITY builds must set PERL_IMPLICIT_CONTEXT
-# endif
-#endif
-
-#if VMG_MULTIPLICITY && defined(USE_ITHREADS) && defined(dMY_CXT) && defined(MY_CXT) && defined(START_MY_CXT) && defined(MY_CXT_INIT) && (defined(MY_CXT_CLONE) || defined(dMY_CXT_SV))
-# ifndef VMG_THREADSAFE
-#  define VMG_THREADSAFE 1
-# endif
-# ifndef MY_CXT_CLONE
-#  define MY_CXT_CLONE \
-    dMY_CXT_SV;                                                      \
-    my_cxt_t *my_cxtp = (my_cxt_t*)SvPVX(newSV(sizeof(my_cxt_t)-1)); \
-    Copy(INT2PTR(my_cxt_t*, SvUV(my_cxt_sv)), my_cxtp, 1, my_cxt_t); \
-    sv_setuv(my_cxt_sv, PTR2UV(my_cxtp))
-# endif
-#else
-# undef  VMG_THREADSAFE
-# define VMG_THREADSAFE 0
-# undef  dMY_CXT
-# define dMY_CXT      dNOOP
-# undef  MY_CXT
-# define MY_CXT       vmg_globaldata
-# undef  START_MY_CXT
-# define START_MY_CXT STATIC my_cxt_t MY_CXT;
-# undef  MY_CXT_INIT
-# define MY_CXT_INIT  NOOP
-# undef  MY_CXT_CLONE
-# define MY_CXT_CLONE NOOP
-#endif
-
-#if VMG_THREADSAFE
-# define VMG_LOCK(M)   MUTEX_LOCK(M)
-# define VMG_UNLOCK(M) MUTEX_UNLOCK(M)
-#else
-# define VMG_LOCK(M)
-# define VMG_UNLOCK(M)
-#endif
-
-/* --- Compatibility ------------------------------------------------------- */
+#define XSH_PACKAGE "Variable::Magic"
 
-#ifndef Newx
-# define Newx(v, n, c) New(0, v, n, c)
-#endif
-
-#ifndef SvMAGIC_set
-# define SvMAGIC_set(sv, val) (SvMAGIC(sv) = (val))
-#endif
-
-#ifndef SvRV_const
-# define SvRV_const(sv) SvRV((SV *) sv)
-#endif
-
-#ifndef SvREFCNT_inc_simple_void
-# define SvREFCNT_inc_simple_void(sv) ((void) SvREFCNT_inc(sv))
-#endif
-
-#ifndef mPUSHu
-# define mPUSHu(U) PUSHs(sv_2mortal(newSVuv(U)))
-#endif
-
-#ifndef PERL_MAGIC_ext
-# define PERL_MAGIC_ext '~'
-#endif
-
-#ifndef PERL_MAGIC_tied
-# define PERL_MAGIC_tied 'P'
-#endif
+#include "xsh/caps.h"
+#include "xsh/util.h"
 
-#ifndef MGf_LOCAL
-# define MGf_LOCAL 0
-#endif
-
-#ifndef IN_PERL_COMPILETIME
-# define IN_PERL_COMPILETIME (PL_curcop == &PL_compiling)
-#endif
-
-#ifndef OP_NAME
-# define OP_NAME(O) (PL_op_name[(O)->op_type])
-#endif
-
-#ifndef OP_CLASS
-# define OP_CLASS(O) (PL_opargs[(O)->op_type] & OA_CLASS_MASK)
-#endif
-
-#ifdef DEBUGGING
-# define VMG_ASSERT(C) assert(C)
-#else
-# define VMG_ASSERT(C)
-#endif
+/* ... Features ............................................................ */
 
 /* uvar magic and Hash::Util::FieldHash were commited with 28419, but we only
  * enable them on 5.10 */
-#if VMG_HAS_PERL(5, 10, 0)
+#if XSH_HAS_PERL(5, 10, 0)
 # define VMG_UVAR 1
 #else
 # define VMG_UVAR 0
 #endif
 
-#if VMG_HAS_PERL_MAINT(5, 11, 0, 32969) || VMG_HAS_PERL(5, 12, 0)
+#if XSH_HAS_PERL_MAINT(5, 11, 0, 32969) || XSH_HAS_PERL(5, 12, 0)
 # define VMG_COMPAT_SCALAR_LENGTH_NOLEN 1
 #else
 # define VMG_COMPAT_SCALAR_LENGTH_NOLEN 0
 #endif
 
-#if VMG_HAS_PERL(5, 17, 4)
+#if XSH_HAS_PERL(5, 17, 4)
 # define VMG_COMPAT_SCALAR_NOLEN 1
 #else
 # define VMG_COMPAT_SCALAR_NOLEN 0
@@ -169,9 +41,9 @@
 
 /* Applied to dev-5.9 as 25854, integrated to maint-5.8 as 28160, partially
  * reverted to dev-5.11 as 9cdcb38b */
-#if VMG_HAS_PERL_MAINT(5, 8, 9, 28160) || VMG_HAS_PERL_MAINT(5, 9, 3, 25854) || VMG_HAS_PERL(5, 10, 0)
+#if XSH_HAS_PERL_MAINT(5, 8, 9, 28160) || XSH_HAS_PERL_MAINT(5, 9, 3, 25854) || XSH_HAS_PERL(5, 10, 0)
 # ifndef VMG_COMPAT_ARRAY_PUSH_NOLEN
-#  if VMG_HAS_PERL(5, 11, 0)
+#  if XSH_HAS_PERL(5, 11, 0)
 #   define VMG_COMPAT_ARRAY_PUSH_NOLEN 0
 #  else
 #   define VMG_COMPAT_ARRAY_PUSH_NOLEN 1
@@ -190,76 +62,43 @@
 #endif
 
 /* Applied to dev-5.11 as 34908 */
-#if VMG_HAS_PERL_MAINT(5, 11, 0, 34908) || VMG_HAS_PERL(5, 12, 0)
+#if XSH_HAS_PERL_MAINT(5, 11, 0, 34908) || XSH_HAS_PERL(5, 12, 0)
 # define VMG_COMPAT_ARRAY_UNSHIFT_NOLEN_VOID 1
 #else
 # define VMG_COMPAT_ARRAY_UNSHIFT_NOLEN_VOID 0
 #endif
 
 /* Applied to dev-5.9 as 31473 (see #43357), integrated to maint-5.8 as 32542 */
-#if VMG_HAS_PERL_MAINT(5, 8, 9, 32542) || VMG_HAS_PERL_MAINT(5, 9, 5, 31473) || VMG_HAS_PERL(5, 10, 0)
+#if XSH_HAS_PERL_MAINT(5, 8, 9, 32542) || XSH_HAS_PERL_MAINT(5, 9, 5, 31473) || XSH_HAS_PERL(5, 10, 0)
 # define VMG_COMPAT_ARRAY_UNDEF_CLEAR 1
 #else
 # define VMG_COMPAT_ARRAY_UNDEF_CLEAR 0
 #endif
 
-#if VMG_HAS_PERL(5, 11, 0)
+#if XSH_HAS_PERL(5, 11, 0)
 # define VMG_COMPAT_HASH_DELETE_NOUVAR_VOID 1
 #else
 # define VMG_COMPAT_HASH_DELETE_NOUVAR_VOID 0
 #endif
 
-#if VMG_HAS_PERL(5, 17, 0)
+#if XSH_HAS_PERL(5, 17, 0)
 # define VMG_COMPAT_CODE_COPY_CLONE 1
 #else
 # define VMG_COMPAT_CODE_COPY_CLONE 0
 #endif
 
-#if VMG_HAS_PERL(5, 13, 2)
+#if XSH_HAS_PERL(5, 13, 2)
 # define VMG_COMPAT_GLOB_GET 1
 #else
 # define VMG_COMPAT_GLOB_GET 0
 #endif
 
-#define VMG_PROPAGATE_ERRSV_NEEDS_TRAMPOLINE (VMG_HAS_PERL(5, 10, 0) && !VMG_HAS_PERL(5, 10, 1))
-
-/* NewOp() isn't public in perl 5.8.0. */
-#define VMG_RESET_RMG_NEEDS_TRAMPOLINE (VMG_UVAR && (VMG_THREADSAFE || !VMG_HAS_PERL(5, 8, 1)))
-
-/* ... Bug-free mg_magical ................................................. */
-
-/* See the discussion at http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2008-01/msg00036.html */
-
-#if VMG_HAS_PERL(5, 11, 3)
-
-#define vmg_mg_magical(S) mg_magical(S)
-
-#else
+/* ... Trampoline ops ...................................................... */
 
-static void vmg_mg_magical(SV *sv) {
- const MAGIC *mg;
+#define VMG_PROPAGATE_ERRSV_NEEDS_TRAMPOLINE (XSH_HAS_PERL(5, 10, 0) && !XSH_HAS_PERL(5, 10, 1))
 
- SvMAGICAL_off(sv);
- if ((mg = SvMAGIC(sv))) {
-  do {
-   const MGVTBL* const vtbl = mg->mg_virtual;
-   if (vtbl) {
-    if (vtbl->svt_get && !(mg->mg_flags & MGf_GSKIP))
-     SvGMAGICAL_on(sv);
-    if (vtbl->svt_set)
-     SvSMAGICAL_on(sv);
-    if (vtbl->svt_clear)
-     SvRMAGICAL_on(sv);
-   }
-  } while ((mg = mg->mg_moremagic));
-  if (!(SvFLAGS(sv) & (SVs_GMG|SVs_SMG)))
-   SvRMAGICAL_on(sv);
- }
-}
-
-#endif
-
-/* --- Trampoline ops ------------------------------------------------------ */
+/* NewOp() isn't public in perl 5.8.0. */
+#define VMG_RESET_RMG_NEEDS_TRAMPOLINE (VMG_UVAR && (XSH_THREADSAFE || !XSH_HAS_PERL(5, 8, 1)))
 
 #define VMG_NEEDS_TRAMPOLINE VMG_PROPAGATE_ERRSV_NEEDS_TRAMPOLINE || VMG_RESET_RMG_NEEDS_TRAMPOLINE
 
@@ -298,7 +137,86 @@ static OP *vmg_trampoline_bump(pTHX_ vmg_trampoline *t, SV *sv, OP *o) {
 
 #endif /* VMG_NEEDS_TRAMPOLINE */
 
-/* --- Cleaner version of sv_magicext() ------------------------------------ */
+/* --- Compatibility ------------------------------------------------------- */
+
+#ifndef Newx
+# define Newx(v, n, c) New(0, v, n, c)
+#endif
+
+#ifndef SvMAGIC_set
+# define SvMAGIC_set(sv, val) (SvMAGIC(sv) = (val))
+#endif
+
+#ifndef SvRV_const
+# define SvRV_const(sv) SvRV((SV *) sv)
+#endif
+
+#ifndef SvREFCNT_inc_simple_void
+# define SvREFCNT_inc_simple_void(sv) ((void) SvREFCNT_inc(sv))
+#endif
+
+#ifndef mPUSHu
+# define mPUSHu(U) PUSHs(sv_2mortal(newSVuv(U)))
+#endif
+
+#ifndef PERL_MAGIC_ext
+# define PERL_MAGIC_ext '~'
+#endif
+
+#ifndef PERL_MAGIC_tied
+# define PERL_MAGIC_tied 'P'
+#endif
+
+#ifndef MGf_LOCAL
+# define MGf_LOCAL 0
+#endif
+
+#ifndef IN_PERL_COMPILETIME
+# define IN_PERL_COMPILETIME (PL_curcop == &PL_compiling)
+#endif
+
+#ifndef OP_NAME
+# define OP_NAME(O) (PL_op_name[(O)->op_type])
+#endif
+
+#ifndef OP_CLASS
+# define OP_CLASS(O) (PL_opargs[(O)->op_type] & OA_CLASS_MASK)
+#endif
+
+/* ... Bug-free mg_magical ................................................. */
+
+/* See the discussion at http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2008-01/msg00036.html */
+
+#if XSH_HAS_PERL(5, 11, 3)
+
+#define vmg_mg_magical(S) mg_magical(S)
+
+#else
+
+static void vmg_mg_magical(SV *sv) {
+ const MAGIC *mg;
+
+ SvMAGICAL_off(sv);
+ if ((mg = SvMAGIC(sv))) {
+  do {
+   const MGVTBL* const vtbl = mg->mg_virtual;
+   if (vtbl) {
+    if (vtbl->svt_get && !(mg->mg_flags & MGf_GSKIP))
+     SvGMAGICAL_on(sv);
+    if (vtbl->svt_set)
+     SvSMAGICAL_on(sv);
+    if (vtbl->svt_clear)
+     SvRMAGICAL_on(sv);
+   }
+  } while ((mg = mg->mg_moremagic));
+  if (!(SvFLAGS(sv) & (SVs_GMG|SVs_SMG)))
+   SvRMAGICAL_on(sv);
+ }
+}
+
+#endif
+
+/* ... Cleaner version of sv_magicext() .................................... */
 
 static MAGIC *vmg_sv_magicext(pTHX_ SV *sv, SV *obj, const MGVTBL *vtbl, const void *ptr, I32 len) {
 #define vmg_sv_magicext(S, O, V, P, L) vmg_sv_magicext(aTHX_ (S), (O), (V), (P), (L))
@@ -327,7 +245,7 @@ static MAGIC *vmg_sv_magicext(pTHX_ SV *sv, SV *obj, const MGVTBL *vtbl, const v
  return mg;
 }
 
-/* --- Safe version of call_sv() ------------------------------------------- */
+/* ... Safe version of call_sv() ........................................... */
 
 static I32 vmg_call_sv(pTHX_ SV *sv, I32 flags, int (*cleanup)(pTHX_ void *), void *ud) {
 #define vmg_call_sv(S, F, C, U) vmg_call_sv(aTHX_ (S), (F), (C), (U))
@@ -352,7 +270,7 @@ static I32 vmg_call_sv(pTHX_ SV *sv, I32 flags, int (*cleanup)(pTHX_ void *), vo
      Perl_warn(aTHX_ "%s", SvPV_nolen(ERRSV));
     SvCUR_set(ERRSV, 0);
    }
-#if VMG_HAS_PERL(5, 10, 0) || defined(PL_parser)
+#if XSH_HAS_PERL(5, 10, 0) || defined(PL_parser)
    if (PL_parser)
     ++PL_parser->error_count;
 #elif defined(PL_error_count)
@@ -389,10 +307,10 @@ typedef enum {
  OPc_PVOP,
  OPc_LOOP,
  OPc_COP,
-#if VMG_HAS_PERL(5, 21, 5)
+#if XSH_HAS_PERL(5, 21, 5)
  OPc_METHOP,
 #endif
-#if VMG_HAS_PERL(5, 21, 7)
+#if XSH_HAS_PERL(5, 21, 7)
  OPc_UNOP_AUX,
 #endif
  OPc_MAX
@@ -411,10 +329,10 @@ static const char *const vmg_opclassnames[] = {
  "B::PVOP",
  "B::LOOP",
  "B::COP",
-#if VMG_HAS_PERL(5, 21, 5)
+#if XSH_HAS_PERL(5, 21, 5)
  "B::METHOP",
 #endif
-#if VMG_HAS_PERL(5, 21, 7)
+#if XSH_HAS_PERL(5, 21, 7)
  "B::UNOP_AUX",
 #endif
  NULL
@@ -428,7 +346,7 @@ static opclass vmg_opclass(pTHX_ const OP *o) {
 #endif
 
  if (o->op_type == 0) {
-#if VMG_HAS_PERL(5, 21, 7)
+#if XSH_HAS_PERL(5, 21, 7)
   if (o->op_targ == OP_NEXTSTATE || o->op_targ == OP_DBSTATE)
    return OPc_COP;
 #endif
@@ -475,11 +393,11 @@ static opclass vmg_opclass(pTHX_ const OP *o) {
    return OPc_PADOP;
   case OA_PVOP_OR_SVOP:
    return (
-#if VMG_HAS_PERL(5, 13, 7)
+#if XSH_HAS_PERL(5, 13, 7)
            (o->op_type != OP_CUSTOM) &&
 #endif
            (o->op_private & (OPpTRANS_TO_UTF|OPpTRANS_FROM_UTF)))
-#if defined(USE_ITHREADS) && VMG_HAS_PERL(5, 8, 9)
+#if defined(USE_ITHREADS) && XSH_HAS_PERL(5, 8, 9)
            ? OPc_PADOP : OPc_PVOP;
 #else
            ? OPc_SVOP : OPc_PVOP;
@@ -504,11 +422,11 @@ static opclass vmg_opclass(pTHX_ const OP *o) {
     return OPc_BASEOP;
    else
     return OPc_PVOP;
-#if VMG_HAS_PERL(5, 21, 5)
+#if XSH_HAS_PERL(5, 21, 5)
   case OA_METHOP:
    return OPc_METHOP;
 #endif
-#if VMG_HAS_PERL(5, 21, 7)
+#if XSH_HAS_PERL(5, 21, 7)
   case OA_UNOP_AUX:
    return OPc_UNOP_AUX;
 #endif
@@ -522,9 +440,7 @@ static opclass vmg_opclass(pTHX_ const OP *o) {
 static const char vmg_invalid_wiz[] = "Invalid wizard object";
 static const char vmg_wrongargnum[] = "Wrong number of arguments";
 
-/* --- Context-safe global data -------------------------------------------- */
-
-#define MY_CXT_KEY __PACKAGE__ "::_guts" XS_VERSION
+/* --- Thread-local storage ------------------------------------------------ */
 
 typedef struct {
  HV             *b__op_stashes[OPc_MAX];
@@ -536,13 +452,35 @@ typedef struct {
 #if VMG_RESET_RMG_NEEDS_TRAMPOLINE
  vmg_trampoline  reset_rmg;
 #endif
-} my_cxt_t;
+} xsh_user_cxt_t;
+
+#if XSH_THREADSAFE
+
+static void xsh_user_clone(pTHX_ const xsh_user_cxt_t *old_cxt, xsh_user_cxt_t *new_cxt) {
+ int c;
+
+ for (c = OPc_NULL; c < OPc_MAX; ++c) {
+  new_cxt->b__op_stashes[c] = old_cxt->b__op_stashes[c]
+                              ? gv_stashpv(vmg_opclassnames[c], 1)
+                              : NULL;
+ }
+
+ new_cxt->depth        = old_cxt->depth;
+ new_cxt->freed_tokens = NULL;
+
+ return;
+}
+
+
+#endif /* XSH_THREADSAFE */
 
-START_MY_CXT
+#define XSH_THREADS_NEED_TEARDOWN_LATE 1
+
+#include "xsh/threads.h"
 
 /* --- <vmg_vtable> structure ---------------------------------------------- */
 
-#if VMG_THREADSAFE
+#if XSH_THREADSAFE
 
 typedef struct {
  MGVTBL *vtbl;
@@ -567,9 +505,9 @@ static perl_mutex vmg_vtable_refcount_mutex;
 
 static vmg_vtable *vmg_vtable_dup(pTHX_ vmg_vtable *t) {
 #define vmg_vtable_dup(T) vmg_vtable_dup(aTHX_ (T))
- VMG_LOCK(&vmg_vtable_refcount_mutex);
+ XSH_LOCK(&vmg_vtable_refcount_mutex);
  ++t->refcount;
- VMG_UNLOCK(&vmg_vtable_refcount_mutex);
+ XSH_UNLOCK(&vmg_vtable_refcount_mutex);
 
  return t;
 }
@@ -578,9 +516,9 @@ static void vmg_vtable_free(pTHX_ vmg_vtable *t) {
 #define vmg_vtable_free(T) vmg_vtable_free(aTHX_ (T))
  U32 refcount;
 
- VMG_LOCK(&vmg_vtable_refcount_mutex);
+ XSH_LOCK(&vmg_vtable_refcount_mutex);
  refcount = --t->refcount;
- VMG_UNLOCK(&vmg_vtable_refcount_mutex);
+ XSH_UNLOCK(&vmg_vtable_refcount_mutex);
 
  if (!refcount) {
   PerlMemShared_free(t->vtbl);
@@ -588,7 +526,7 @@ static void vmg_vtable_free(pTHX_ vmg_vtable *t) {
  }
 }
 
-#else /* VMG_THREADSAFE */
+#else /* XSH_THREADSAFE */
 
 typedef MGVTBL vmg_vtable;
 
@@ -605,7 +543,7 @@ static vmg_vtable *vmg_vtable_alloc(pTHX) {
 
 #define vmg_vtable_free(T) Safefree(T)
 
-#endif /* !VMG_THREADSAFE */
+#endif /* !XSH_THREADSAFE */
 
 /* --- <vmg_wizard> structure ---------------------------------------------- */
 
@@ -682,7 +620,7 @@ static void vmg_wizard_free(pTHX_ vmg_wizard *w) {
  return;
 }
 
-#if VMG_THREADSAFE
+#if XSH_THREADSAFE
 
 #define VMG_CLONE_CB(N) \
  z->cb_ ## N = (w->cb_ ## N) ? SvREFCNT_inc(sv_dup(w->cb_ ## N, params)) \
@@ -722,7 +660,7 @@ static const vmg_wizard *vmg_wizard_dup(pTHX_ const vmg_wizard *w, CLONE_PARAMS
  return z;
 }
 
-#endif /* VMG_THREADSAFE */
+#endif /* XSH_THREADSAFE */
 
 #define vmg_wizard_id(W) PTR2IV(vmg_vtable_vtbl((W)->vtable))
 
@@ -734,7 +672,7 @@ static int vmg_wizard_sv_free(pTHX_ SV *sv, MAGIC *mg) {
  return 0;
 }
 
-#if VMG_THREADSAFE
+#if XSH_THREADSAFE
 
 static int vmg_wizard_sv_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *params) {
  mg->mg_ptr = (char *) vmg_wizard_dup((const vmg_wizard *) mg->mg_ptr, params);
@@ -742,7 +680,7 @@ static int vmg_wizard_sv_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *params) {
  return 0;
 }
 
-#endif /* VMG_THREADSAFE */
+#endif /* XSH_THREADSAFE */
 
 static MGVTBL vmg_wizard_sv_vtbl = {
  NULL,               /* get */
@@ -751,7 +689,7 @@ static MGVTBL vmg_wizard_sv_vtbl = {
  NULL,               /* clear */
  vmg_wizard_sv_free, /* free */
  NULL,               /* copy */
-#if VMG_THREADSAFE
+#if XSH_THREADSAFE
  vmg_wizard_sv_dup,  /* dup */
 #else
  NULL,               /* dup */
@@ -765,7 +703,7 @@ static SV *vmg_wizard_sv_new(pTHX_ const vmg_wizard *w) {
 #define vmg_wizard_sv_new(W) vmg_wizard_sv_new(aTHX_ (W))
  SV *wiz;
 
-#if VMG_THREADSAFE
+#if XSH_THREADSAFE
  wiz = newSV(0);
 #else
  wiz = newSViv(PTR2IV(w));
@@ -778,7 +716,7 @@ static SV *vmg_wizard_sv_new(pTHX_ const vmg_wizard *w) {
  return wiz;
 }
 
-#if VMG_THREADSAFE
+#if XSH_THREADSAFE
 
 #define vmg_sv_has_wizard_type(S) (SvTYPE(S) >= SVt_PVMG)
 
@@ -793,13 +731,13 @@ static const vmg_wizard *vmg_wizard_from_sv_nocheck(const SV *wiz) {
  return NULL;
 }
 
-#else /* VMG_THREADSAFE */
+#else /* XSH_THREADSAFE */
 
 #define vmg_sv_has_wizard_type(S) SvIOK(S)
 
 #define vmg_wizard_from_sv_nocheck(W) INT2PTR(const vmg_wizard *, SvIVX(W))
 
-#endif /* !VMG_THREADSAFE */
+#endif /* !XSH_THREADSAFE */
 
 #define vmg_wizard_from_sv(W) (vmg_sv_has_wizard_type(W) ? vmg_wizard_from_sv_nocheck(W) : NULL)
 
@@ -862,7 +800,7 @@ static SV *vmg_data_new(pTHX_ SV *ctor, SV *sv, SV **args, I32 items) {
 
  SPAGAIN;
  nsv = POPs;
-#if VMG_HAS_PERL(5, 8, 3)
+#if XSH_HAS_PERL(5, 8, 3)
  SvREFCNT_inc_simple_void(nsv); /* Or it will be destroyed in FREETMPS */
 #else
  nsv = sv_newref(nsv);          /* Workaround some bug in SvREFCNT_inc() */
@@ -899,7 +837,7 @@ typedef struct {
 
 static void vmg_mg_del(pTHX_ SV *sv, MAGIC *prevmagic, MAGIC *mg, MAGIC *moremagic) {
 #define vmg_mg_del(S, P, M, N) vmg_mg_del(aTHX_ (S), (P), (M), (N))
- dMY_CXT;
+ dXSH_CXT;
 
  if (prevmagic)
   prevmagic->mg_moremagic = moremagic;
@@ -923,9 +861,9 @@ static void vmg_mg_del(pTHX_ SV *sv, MAGIC *prevmagic, MAGIC *mg, MAGIC *moremag
  }
 #endif /* VMG_UVAR */
 
- if (MY_CXT.depth) {
-  mg->mg_moremagic    = MY_CXT.freed_tokens;
-  MY_CXT.freed_tokens = mg;
+ if (XSH_CXT.depth) {
+  mg->mg_moremagic     = XSH_CXT.freed_tokens;
+  XSH_CXT.freed_tokens = mg;
  } else {
   mg->mg_moremagic = NULL;
   Safefree(mg);
@@ -1110,7 +1048,7 @@ static UV vmg_dispell(pTHX_ SV *sv, const vmg_wizard *w) {
 #define VMG_OP_INFO_NAME   1
 #define VMG_OP_INFO_OBJECT 2
 
-#if VMG_THREADSAFE
+#if XSH_THREADSAFE
 static perl_mutex vmg_op_name_init_mutex;
 #endif
 
@@ -1121,22 +1059,22 @@ static void vmg_op_info_init(pTHX_ unsigned int opinfo) {
 #define vmg_op_info_init(W) vmg_op_info_init(aTHX_ (W))
  switch (opinfo) {
   case VMG_OP_INFO_NAME:
-   VMG_LOCK(&vmg_op_name_init_mutex);
+   XSH_LOCK(&vmg_op_name_init_mutex);
    if (!vmg_op_name_init) {
     OPCODE t;
     for (t = 0; t < OP_max; ++t)
      vmg_op_name_len[t] = strlen(PL_op_name[t]);
     vmg_op_name_init = 1;
    }
-   VMG_UNLOCK(&vmg_op_name_init_mutex);
+   XSH_UNLOCK(&vmg_op_name_init_mutex);
    break;
   case VMG_OP_INFO_OBJECT: {
-   dMY_CXT;
-   if (!MY_CXT.b__op_stashes[0]) {
+   dXSH_CXT;
+   if (!XSH_CXT.b__op_stashes[0]) {
     int c;
     require_pv("B.pm");
     for (c = OPc_NULL; c < OPc_MAX; ++c)
-     MY_CXT.b__op_stashes[c] = gv_stashpv(vmg_opclassnames[c], 1);
+     XSH_CXT.b__op_stashes[c] = gv_stashpv(vmg_opclassnames[c], 1);
    }
    break;
   }
@@ -1160,9 +1098,9 @@ static SV *vmg_op_info(pTHX_ unsigned int opinfo) {
    return sv_2mortal(newSVpvn(name, name_len));
   }
   case VMG_OP_INFO_OBJECT: {
-   dMY_CXT;
+   dXSH_CXT;
    return sv_bless(sv_2mortal(newRV_noinc(newSViv(PTR2IV(PL_op)))),
-                   MY_CXT.b__op_stashes[vmg_opclass(PL_op)]);
+                   XSH_CXT.b__op_stashes[vmg_opclass(PL_op)]);
   }
   default:
    break;
@@ -1179,16 +1117,16 @@ static SV *vmg_op_info(pTHX_ unsigned int opinfo) {
 #define VMG_CB_CALL_GUARD      4
 
 static int vmg_dispell_guard_oncroak(pTHX_ void *ud) {
- dMY_CXT;
+ dXSH_CXT;
 
- MY_CXT.depth--;
+ XSH_CXT.depth--;
 
  /* If we're at the upmost magic call and we're about to die, we can just free
   * the tokens right now, since we will jump past the problematic part of our
   * caller. */
- if (MY_CXT.depth == 0 && MY_CXT.freed_tokens) {
-  vmg_magic_chain_free(MY_CXT.freed_tokens, NULL);
-  MY_CXT.freed_tokens = NULL;
+ if (XSH_CXT.depth == 0 && XSH_CXT.freed_tokens) {
+  vmg_magic_chain_free(XSH_CXT.freed_tokens, NULL);
+  XSH_CXT.freed_tokens = NULL;
  }
 
  return 1;
@@ -1200,7 +1138,7 @@ static int vmg_dispell_guard_free(pTHX_ SV *sv, MAGIC *mg) {
  return 0;
 }
 
-#if VMG_THREADSAFE
+#if XSH_THREADSAFE
 
 static int vmg_dispell_guard_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *params) {
  /* The freed magic tokens aren't cloned by perl because it cannot reach them
@@ -1211,7 +1149,7 @@ static int vmg_dispell_guard_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *params) {
  return 0;
 }
 
-#endif /* VMG_THREADSAFE */
+#endif /* XSH_THREADSAFE */
 
 static MGVTBL vmg_dispell_guard_vtbl = {
  NULL,                   /* get */
@@ -1220,7 +1158,7 @@ static MGVTBL vmg_dispell_guard_vtbl = {
  NULL,                   /* clear */
  vmg_dispell_guard_free, /* free */
  NULL,                   /* copy */
-#if VMG_THREADSAFE
+#if XSH_THREADSAFE
  vmg_dispell_guard_dup,  /* dup */
 #else
  NULL,                   /* dup */
@@ -1272,12 +1210,12 @@ static int vmg_cb_call(pTHX_ SV *cb, unsigned int flags, SV *sv, ...) {
  PUTBACK;
 
  if (flags & VMG_CB_CALL_GUARD) {
-  dMY_CXT;
-  MY_CXT.depth++;
+  dXSH_CXT;
+  XSH_CXT.depth++;
   vmg_call_sv(cb, G_SCALAR, vmg_dispell_guard_oncroak, NULL);
-  MY_CXT.depth--;
-  if (MY_CXT.depth == 0 && MY_CXT.freed_tokens)
-   chain = &MY_CXT.freed_tokens;
+  XSH_CXT.depth--;
+  if (XSH_CXT.depth == 0 && XSH_CXT.freed_tokens)
+   chain = &XSH_CXT.freed_tokens;
  } else {
   vmg_call_sv(cb, G_SCALAR, 0, NULL);
  }
@@ -1349,7 +1287,7 @@ static int vmg_svt_set(pTHX_ SV *sv, MAGIC *mg) {
 static U32 vmg_sv_len(pTHX_ SV *sv) {
 #define vmg_sv_len(S) vmg_sv_len(aTHX_ (S))
  STRLEN len;
-#if VMG_HAS_PERL(5, 9, 3)
+#if XSH_HAS_PERL(5, 9, 3)
  const U8 *s = VOID2(const U8 *, VOID2(const void *, SvPV_const(sv, len)));
 #else
  U8 *s = SvPV(sv, len);
@@ -1426,7 +1364,7 @@ static int vmg_svt_clear(pTHX_ SV *sv, MAGIC *mg) {
  const vmg_wizard *w = vmg_wizard_from_mg_nocheck(mg);
  unsigned int flags  = w->opinfo;
 
-#if !VMG_HAS_PERL(5, 12, 0)
+#if !XSH_HAS_PERL(5, 12, 0)
  flags |= VMG_CB_CALL_GUARD;
 #endif
 
@@ -1496,14 +1434,14 @@ static int vmg_svt_free_cleanup(pTHX_ void *ud_) {
 
 #if VMG_PROPAGATE_ERRSV_NEEDS_TRAMPOLINE
    if (optype == OP_LEAVETRY) {
-    dMY_CXT;
-    PL_op = vmg_trampoline_bump(&MY_CXT.propagate_errsv, errsv, PL_op);
+    dXSH_CXT;
+    PL_op = vmg_trampoline_bump(&XSH_CXT.propagate_errsv, errsv, PL_op);
    } else if (optype == OP_LEAVEEVAL) {
     SV *guard = sv_newmortal();
     vmg_sv_magicext(guard, errsv, &vmg_propagate_errsv_vtbl, NULL, 0);
    }
 #else /* !VMG_PROPAGATE_ERRSV_NEEDS_TRAMPOLINE */
-# if !VMG_HAS_PERL(5, 8, 9)
+# if !XSH_HAS_PERL(5, 8, 9)
    {
     SV *guard = sv_newmortal();
     vmg_sv_magicext(guard, errsv, &vmg_propagate_errsv_vtbl, NULL, 0);
@@ -1556,7 +1494,7 @@ static int vmg_svt_free(pTHX_ SV *sv, MAGIC *mg) {
  /* So that it survives the temp cleanup below */
  SvREFCNT_inc_simple_void(sv);
 
-#if !(VMG_HAS_PERL_MAINT(5, 11, 0, 32686) || VMG_HAS_PERL(5, 12, 0))
+#if !(XSH_HAS_PERL_MAINT(5, 11, 0, 32686) || XSH_HAS_PERL(5, 12, 0))
  /* The previous magic tokens were freed but the magic chain wasn't updated, so
   * if you access the sv from the callback the old deleted magics will trigger
   * and cause memory misreads. Change 32686 solved it that way : */
@@ -1586,15 +1524,15 @@ static int vmg_svt_free(pTHX_ SV *sv, MAGIC *mg) {
  PUTBACK;
 
  {
-  dMY_CXT;
-  MY_CXT.depth++;
+  dXSH_CXT;
+  XSH_CXT.depth++;
   vmg_call_sv(w->cb_free, G_SCALAR, vmg_svt_free_cleanup, &ud);
-  MY_CXT.depth--;
-  if (MY_CXT.depth == 0 && MY_CXT.freed_tokens) {
+  XSH_CXT.depth--;
+  if (XSH_CXT.depth == 0 && XSH_CXT.freed_tokens) {
    /* Free all the tokens in the chain but the current one (if it's present).
     * It will be taken care of by our caller, Perl_mg_free(). */
-   vmg_magic_chain_free(MY_CXT.freed_tokens, mg);
-   MY_CXT.freed_tokens = NULL;
+   vmg_magic_chain_free(XSH_CXT.freed_tokens, mg);
+   XSH_CXT.freed_tokens = NULL;
   }
  }
 
@@ -1620,7 +1558,7 @@ static int vmg_svt_free(pTHX_ SV *sv, MAGIC *mg) {
 
 #define vmg_svt_free_noop vmg_svt_default_noop
 
-#if VMG_HAS_PERL_MAINT(5, 11, 0, 33256) || VMG_HAS_PERL(5, 12, 0)
+#if XSH_HAS_PERL_MAINT(5, 11, 0, 33256) || XSH_HAS_PERL(5, 12, 0)
 # define VMG_SVT_COPY_KEYLEN_TYPE I32
 #else
 # define VMG_SVT_COPY_KEYLEN_TYPE int
@@ -1771,9 +1709,9 @@ static I32 vmg_svt_val(pTHX_ IV action, SV *sv) {
 
 #if VMG_RESET_RMG_NEEDS_TRAMPOLINE
 
-  dMY_CXT;
+  dXSH_CXT;
 
-  PL_op = vmg_trampoline_bump(&MY_CXT.reset_rmg, sv, PL_op);
+  PL_op = vmg_trampoline_bump(&XSH_CXT.reset_rmg, sv, PL_op);
 
 #else /* !VMG_RESET_RMG_NEEDS_TRAMPOLINE */
 
@@ -1807,56 +1745,16 @@ static I32 vmg_svt_val(pTHX_ IV action, SV *sv) {
 
 /* --- Module setup/teardown ----------------------------------------------- */
 
-#if VMG_THREADSAFE
-
-static I32 vmg_loaded = 0;
-
-/* We must use preexistent global mutexes or we will never be able to destroy
- * them. */
-# if VMG_HAS_PERL(5, 9, 3)
-#  define VMG_LOADED_LOCK   MUTEX_LOCK(&PL_my_ctx_mutex)
-#  define VMG_LOADED_UNLOCK MUTEX_UNLOCK(&PL_my_ctx_mutex)
-# else
-#  define VMG_LOADED_LOCK   OP_REFCNT_LOCK
-#  define VMG_LOADED_UNLOCK OP_REFCNT_UNLOCK
-# endif
+#if XSH_THREADSAFE
 
-static void vmg_global_teardown_late_locked(pTHX) {
-#define vmg_global_teardown_late_locked() vmg_global_teardown_late_locked(aTHX)
+static void vmg_global_teardown_late_locked(pTHX_ void *ud) {
+#define vmg_global_teardown_late_locked(UD) vmg_global_teardown_late_locked(aTHX_ (UD))
  MUTEX_DESTROY(&vmg_op_name_init_mutex);
  MUTEX_DESTROY(&vmg_vtable_refcount_mutex);
 
  return;
 }
 
-static int vmg_global_teardown_free(pTHX_ SV *sv, MAGIC *mg) {
- VMG_LOADED_LOCK;
-
- if (vmg_loaded == 0)
-  vmg_global_teardown_late_locked();
-
- VMG_LOADED_UNLOCK;
-
- return 0;
-}
-
-static MGVTBL vmg_global_teardown_vtbl = {
- 0,
- 0,
- 0,
- 0,
- vmg_global_teardown_free
-#if MGf_COPY
- , 0
-#endif
-#if MGf_DUP
- , 0
-#endif
-#if MGf_LOCAL
- , 0
-#endif
-};
-
 static signed char vmg_destruct_level(pTHX) {
 #define vmg_destruct_level() vmg_destruct_level(aTHX)
  signed char lvl;
@@ -1868,21 +1766,21 @@ static signed char vmg_destruct_level(pTHX) {
   const char *s = PerlEnv_getenv("PERL_DESTRUCT_LEVEL");
   if (s) {
    int i;
-#if VMG_HAS_PERL(5, 21, 3)
+#if XSH_HAS_PERL(5, 21, 3)
    if (strEQ(s, "-1")) {
     i = -1;
    } else {
-# if VMG_HAS_PERL(5, 21, 10)
+# if XSH_HAS_PERL(5, 21, 10)
     UV uv;
     if (Perl_grok_atoUV(s, &uv, NULL) && uv <= INT_MAX)
      i = (int) uv;
     else
      i = 0;
-# else /* VMG_HAS_PERL(5, 21, 3) && !VMG_HAS_PERL(5, 21, 10) */
+# else /* XSH_HAS_PERL(5, 21, 3) && !XSH_HAS_PERL(5, 21, 10) */
     i = Perl_grok_atou(s, NULL);
 # endif
    }
-#else /* !VMG_HAS_PERL(5, 21, 3) */
+#else /* !XSH_HAS_PERL(5, 21, 3) */
    i = atoi(s);
 #endif
    if (lvl < i)
@@ -1894,74 +1792,35 @@ static signed char vmg_destruct_level(pTHX) {
  return lvl;
 }
 
-#endif /* VMG_THREADSAFE */
-
-static void vmg_teardown(pTHX_ void *param) {
- dMY_CXT;
-
-#if VMG_THREADSAFE
- VMG_LOADED_LOCK;
+#endif /* XSH_THREADSAFE */
 
- if (vmg_loaded == 1) {
-  vmg_loaded = 0;
-  if (vmg_destruct_level() == 0) {
-   vmg_global_teardown_late_locked();
-  } else {
-   if (!PL_strtab)
-    PL_strtab = newHV();
-   vmg_sv_magicext((SV *) PL_strtab, NULL, &vmg_global_teardown_vtbl, NULL, 0);
-  }
- } else {
-  VMG_ASSERT(vmg_loaded > 1);
-  --vmg_loaded;
- }
-
- VMG_LOADED_UNLOCK;
+static void xsh_user_global_setup(pTHX) {
+#if XSH_THREADSAFE
+ MUTEX_INIT(&vmg_vtable_refcount_mutex);
+ MUTEX_INIT(&vmg_op_name_init_mutex);
 #endif
 
- if (MY_CXT.depth == 0 && MY_CXT.freed_tokens) {
-  vmg_magic_chain_free(MY_CXT.freed_tokens, NULL);
-  MY_CXT.freed_tokens = NULL;
- }
-
  return;
 }
 
-static void vmg_setup(pTHX) {
-#define vmg_setup() vmg_setup(aTHX)
+static void xsh_user_local_setup(pTHX_ xsh_user_cxt_t *cxt) {
  HV *stash;
  int c;
- MY_CXT_INIT;
-
-#if VMG_THREADSAFE
- VMG_LOADED_LOCK;
-
- if (vmg_loaded == 0) {
-  MUTEX_INIT(&vmg_vtable_refcount_mutex);
-  MUTEX_INIT(&vmg_op_name_init_mutex);
-  vmg_loaded = 1;
- } else {
-  VMG_ASSERT(vmg_loaded > 0);
-  ++vmg_loaded;
- }
-
- VMG_LOADED_UNLOCK;
-#endif
 
  for (c = OPc_NULL; c < OPc_MAX; ++c)
-  MY_CXT.b__op_stashes[c] = NULL;
+  cxt->b__op_stashes[c] = NULL;
 
- MY_CXT.depth        = 0;
- MY_CXT.freed_tokens = NULL;
+ cxt->depth        = 0;
+ cxt->freed_tokens = NULL;
 
 #if VMG_PROPAGATE_ERRSV_NEEDS_TRAMPOLINE
- vmg_trampoline_init(&MY_CXT.propagate_errsv, vmg_pp_propagate_errsv);
+ vmg_trampoline_init(&cxt->propagate_errsv, vmg_pp_propagate_errsv);
 #endif
 #if VMG_RESET_RMG_NEEDS_TRAMPOLINE
- vmg_trampoline_init(&MY_CXT.reset_rmg, vmg_pp_reset_rmg);
+ vmg_trampoline_init(&cxt->reset_rmg, vmg_pp_reset_rmg);
 #endif
 
- stash = gv_stashpv(__PACKAGE__, 1);
+ stash = gv_stashpv(XSH_PACKAGE, 1);
  newCONSTSUB(stash, "MGf_COPY",  newSVuv(MGf_COPY));
  newCONSTSUB(stash, "MGf_DUP",   newSVuv(MGf_DUP));
  newCONSTSUB(stash, "MGf_LOCAL", newSVuv(MGf_LOCAL));
@@ -1983,13 +1842,31 @@ static void vmg_setup(pTHX) {
  newCONSTSUB(stash, "VMG_COMPAT_CODE_COPY_CLONE",
                     newSVuv(VMG_COMPAT_CODE_COPY_CLONE));
  newCONSTSUB(stash, "VMG_COMPAT_GLOB_GET", newSVuv(VMG_COMPAT_GLOB_GET));
- newCONSTSUB(stash, "VMG_PERL_PATCHLEVEL", newSVuv(VMG_PERL_PATCHLEVEL));
- newCONSTSUB(stash, "VMG_THREADSAFE",      newSVuv(VMG_THREADSAFE));
- newCONSTSUB(stash, "VMG_FORKSAFE",        newSVuv(VMG_FORKSAFE));
+ newCONSTSUB(stash, "VMG_PERL_PATCHLEVEL", newSVuv(XSH_PERL_PATCHLEVEL));
+ newCONSTSUB(stash, "VMG_THREADSAFE",      newSVuv(XSH_THREADSAFE));
+ newCONSTSUB(stash, "VMG_FORKSAFE",        newSVuv(XSH_FORKSAFE));
  newCONSTSUB(stash, "VMG_OP_INFO_NAME",    newSVuv(VMG_OP_INFO_NAME));
  newCONSTSUB(stash, "VMG_OP_INFO_OBJECT",  newSVuv(VMG_OP_INFO_OBJECT));
 
- call_atexit(vmg_teardown, NULL);
+ return;
+}
+
+static void xsh_user_local_teardown(pTHX_ xsh_user_cxt_t *cxt) {
+ if (cxt->depth == 0 && cxt->freed_tokens) {
+  vmg_magic_chain_free(cxt->freed_tokens, NULL);
+  cxt->freed_tokens = NULL;
+ }
+
+ return;
+}
+
+static void xsh_user_global_teardown(pTHX) {
+#if XSH_THREADSAFE
+ if (vmg_destruct_level() == 0)
+  vmg_global_teardown_late_locked(NULL);
+ else
+  xsh_teardown_late_register(vmg_global_teardown_late_locked, NULL);
+#endif
 
  return;
 }
@@ -2045,43 +1922,19 @@ PROTOTYPES: ENABLE
 
 BOOT:
 {
- vmg_setup();
+ xsh_setup();
 }
 
-#if VMG_THREADSAFE
+#if XSH_THREADSAFE
 
 void
 CLONE(...)
 PROTOTYPE: DISABLE
-PREINIT:
- U32 had_b__op_stash = 0;
- I32 old_depth;
- int c;
 PPCODE:
- {
-  dMY_CXT;
-  for (c = OPc_NULL; c < OPc_MAX; ++c) {
-   if (MY_CXT.b__op_stashes[c])
-    had_b__op_stash |= (((U32) 1) << c);
-  }
-  old_depth = MY_CXT.depth;
- }
- {
-  MY_CXT_CLONE;
-  for (c = OPc_NULL; c < OPc_MAX; ++c) {
-   MY_CXT.b__op_stashes[c] = (had_b__op_stash & (((U32) 1) << c))
-                              ? gv_stashpv(vmg_opclassnames[c], 1) : NULL;
-  }
-  MY_CXT.depth        = old_depth;
-  MY_CXT.freed_tokens = NULL;
-  VMG_LOADED_LOCK;
-  VMG_ASSERT(vmg_loaded > 0);
-  ++vmg_loaded;
-  VMG_LOADED_UNLOCK;
- }
+ xsh_clone();
  XSRETURN(0);
 
-#endif /* VMG_THREADSAFE */
+#endif /* XSH_THREADSAFE */
 
 SV *_wizard(...)
 PROTOTYPE: DISABLE
diff --git a/Makefile.PL b/Makefile.PL
index 4efbec5..9abd407 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -52,13 +52,13 @@ print $is_gcc_34 ? "yes\n" : "no\n";
 
 # Threads, Windows and 5.8.x don't seem to be best friends
 if ($^O eq 'MSWin32' && "$]" < 5.009) {
- push @DEFINES, '-DVMG_MULTIPLICITY=0';
+ push @DEFINES, '-DXSH_MULTIPLICITY=0';
  print "Thread safety disabled for perl 5.8.x on Windows.\n"
 }
 
 # Fork emulation got "fixed" in 5.10.1
 if ($^O eq 'MSWin32' && "$]" < 5.010_001) {
- push @DEFINES, '-DVMG_FORKSAFE=0';
+ push @DEFINES, '-DXSH_FORKSAFE=0';
  print "Fork safety not ensured for perl 5.8.x and 5.10.0 on Windows.\n";
 }
 
diff --git a/xsh/caps.h b/xsh/caps.h
new file mode 100644
index 0000000..4559524
--- /dev/null
+++ b/xsh/caps.h
@@ -0,0 +1,47 @@
+#ifndef XSH_CAPS_H
+#define XSH_CAPS_H 1
+
+#define XSH_HAS_PERL(R, V, S) (PERL_REVISION > (R) || (PERL_REVISION == (R) && (PERL_VERSION > (V) || (PERL_VERSION == (V) && (PERL_SUBVERSION >= (S))))))
+
+#define XSH_HAS_PERL_BRANCH(R, V, S) (PERL_REVISION == (R) && PERL_VERSION == (V) && PERL_SUBVERSION >= (S))
+
+#define XSH_HAS_PERL_EXACT(R, V, S) ((PERL_REVISION == (R)) && (PERL_VERSION == (V)) && (PERL_SUBVERSION == (S)))
+
+#ifndef XSH_PERL_PATCHLEVEL
+# ifdef PERL_PATCHNUM
+#  define XSH_PERL_PATCHLEVEL PERL_PATCHNUM
+# else
+#  define XSH_PERL_PATCHLEVEL 0
+# endif
+#endif
+
+#define XSH_HAS_PERL_MAINT(R, V, S, P) (PERL_REVISION == (R) && PERL_VERSION == (V) && (XSH_PERL_PATCHLEVEL >= (P) || (!XSH_PERL_PATCHLEVEL && PERL_SUBVERSION >= (S))))
+
+#ifndef XSH_MULTIPLICITY
+# if defined(MULTIPLICITY)
+#  define XSH_MULTIPLICITY 1
+# else
+#  define XSH_MULTIPLICITY 0
+# endif
+#endif
+#if XSH_MULTIPLICITY
+# ifndef PERL_IMPLICIT_CONTEXT
+#  error MULTIPLICITY builds must set PERL_IMPLICIT_CONTEXT
+# endif
+# ifndef tTHX
+#  define tTHX PerlInterpreter*
+# endif
+#endif
+
+#if XSH_MULTIPLICITY && defined(USE_ITHREADS) && defined(dMY_CXT) && defined(MY_CXT) && defined(START_MY_CXT) && defined(MY_CXT_INIT) && (defined(MY_CXT_CLONE) || defined(dMY_CXT_SV))
+# define XSH_THREADSAFE 1
+#else
+# define XSH_THREADSAFE 0
+#endif
+
+/* Safe unless stated otherwise in Makefile.PL */
+#ifndef XSH_FORKSAFE
+# define XSH_FORKSAFE 1
+#endif
+
+#endif /* XSH_CAPS_H */
diff --git a/xsh/threads.h b/xsh/threads.h
new file mode 100644
index 0000000..b72c63b
--- /dev/null
+++ b/xsh/threads.h
@@ -0,0 +1,501 @@
+#ifndef XSH_THREADS_H
+#define XSH_THREADS_H 1
+
+#include "caps.h" /* XSH_HAS_PERL(), XSH_THREADSAFE */
+#include "util.h" /* XSH_PACKAGE, dNOOP, NOOP */
+
+#ifndef XSH_THREADS_COMPILE_TIME_PROTECTION
+# define XSH_THREADS_COMPILE_TIME_PROTECTION 0
+#endif
+
+#ifndef XSH_THREADS_USER_CONTEXT
+# define XSH_THREADS_USER_CONTEXT 1
+#endif
+
+#ifndef XSH_THREADS_USER_GLOBAL_SETUP
+# define XSH_THREADS_USER_GLOBAL_SETUP 1
+#endif
+
+#ifndef XSH_THREADS_USER_LOCAL_SETUP
+# define XSH_THREADS_USER_LOCAL_SETUP 1
+#endif
+
+#ifndef XSH_THREADS_USER_LOCAL_TEARDOWN
+# define XSH_THREADS_USER_LOCAL_TEARDOWN 1
+#endif
+
+#ifndef XSH_THREADS_USER_GLOBAL_TEARDOWN
+# define XSH_THREADS_USER_GLOBAL_TEARDOWN 1
+#endif
+
+#ifndef XSH_THREADS_PEEP_CONTEXT
+# define XSH_THREADS_PEEP_CONTEXT 0
+#endif
+
+#ifndef XSH_THREADS_HINTS_CONTEXT
+# define XSH_THREADS_HINTS_CONTEXT 0
+#endif
+
+#ifndef XSH_THREADS_USER_CLONE_NEEDS_DUP
+# define XSH_THREADS_USER_CLONE_NEEDS_DUP 0
+#endif
+
+#if XSH_THREADSAFE && (XSH_THREADS_HINTS_CONTEXT || XSH_THREADS_USER_CLONE_NEEDS_DUP)
+# define XSH_THREADS_CLONE_NEEDS_DUP 1
+#else
+# define XSH_THREADS_CLONE_NEEDS_DUP 0
+#endif
+
+#if defined(XSH_OPS_H) && (!XSH_THREADS_GLOBAL_SETUP || !XSH_THREADS_GLOBAL_TEARDOWN)
+# error settting up hook check functions require global setup/teardown
+#endif
+
+#ifndef XSH_THREADS_NEED_TEARDOWN_LATE
+# define XSH_THREADS_NEED_TEARDOWN_LATE 0
+#endif
+
+#if XSH_THREADS_NEED_TEARDOWN_LATE && (!XSH_THREADS_USER_LOCAL_TEARDOWN || !XSH_THREADS_USER_GLOBAL_TEARDOWN)
+# error you need to declare local or global teardown handlers to use the late teardown feature
+#endif
+
+#if XSH_THREADSAFE
+# ifndef MY_CXT_CLONE
+#  define MY_CXT_CLONE \
+    dMY_CXT_SV;                                                      \
+    my_cxt_t *my_cxtp = (my_cxt_t*)SvPVX(newSV(sizeof(my_cxt_t)-1)); \
+    Copy(INT2PTR(my_cxt_t*, SvUV(my_cxt_sv)), my_cxtp, 1, my_cxt_t); \
+    sv_setuv(my_cxt_sv, PTR2UV(my_cxtp))
+# endif
+#else
+# undef  dMY_CXT
+# define dMY_CXT      dNOOP
+# undef  MY_CXT
+# define MY_CXT       xsh_globaldata
+# undef  START_MY_CXT
+# define START_MY_CXT static my_cxt_t MY_CXT;
+# undef  MY_CXT_INIT
+# define MY_CXT_INIT  NOOP
+# undef  MY_CXT_CLONE
+# define MY_CXT_CLONE NOOP
+#endif
+
+#if XSH_THREADSAFE
+/* We must use preexistent global mutexes or we will never be able to destroy
+ * them. */
+# if XSH_HAS_PERL(5, 9, 3)
+#  define XSH_LOADED_LOCK   MUTEX_LOCK(&PL_my_ctx_mutex)
+#  define XSH_LOADED_UNLOCK MUTEX_UNLOCK(&PL_my_ctx_mutex)
+# else
+#  define XSH_LOADED_LOCK   OP_REFCNT_LOCK
+#  define XSH_LOADED_UNLOCK OP_REFCNT_UNLOCK
+# endif
+#else
+# define XSH_LOADED_LOCK   NOOP
+# define XSH_LOADED_UNLOCK NOOP
+#endif
+
+static I32 xsh_loaded = 0;
+
+#if XSH_THREADSAFE && XSH_THREADS_COMPILE_TIME_PROTECTION
+
+#define PTABLE_USE_DEFAULT 1
+
+#include "ptable.h"
+
+#define ptable_loaded_store(T, K, V) ptable_default_store(aPTBL_ (T), (K), (V))
+#define ptable_loaded_delete(T, K)   ptable_default_delete(aPTBL_ (T), (K))
+#define ptable_loaded_free(T)        ptable_default_free(aPTBL_ (T))
+
+static ptable *xsh_loaded_cxts = NULL;
+
+static int xsh_is_loaded(pTHX_ void *cxt) {
+#define xsh_is_loaded(C) xsh_is_loaded(aTHX_ (C))
+ int res = 0;
+
+ XSH_LOADED_LOCK;
+ if (xsh_loaded_cxts && ptable_fetch(xsh_loaded_cxts, cxt))
+  res = 1;
+ XSH_LOADED_UNLOCK;
+
+ return res;
+}
+
+static int xsh_set_loaded_locked(pTHX_ void *cxt) {
+#define xsh_set_loaded_locked(C) xsh_set_loaded_locked(aTHX_ (C))
+ int global_setup = 0;
+
+ if (xsh_loaded <= 0) {
+  XSH_ASSERT(xsh_loaded == 0);
+  XSH_ASSERT(!xsh_loaded_cxts);
+  xsh_loaded_cxts = ptable_new(4);
+  global_setup   = 1;
+ }
+ ++xsh_loaded;
+ XSH_ASSERT(xsh_loaded_cxts);
+ ptable_loaded_store(xsh_loaded_cxts, cxt, cxt);
+
+ return global_setup;
+}
+
+static int xsh_clear_loaded_locked(pTHX_ void *cxt) {
+#define xsh_clear_loaded_locked(C) xsh_clear_loaded_locked(aTHX_ (C))
+ int global_teardown = 0;
+
+ if (xsh_loaded > 1) {
+  XSH_ASSERT(xsh_loaded_cxts);
+  ptable_loaded_delete(xsh_loaded_cxts, cxt);
+  --xsh_loaded;
+ } else if (xsh_loaded_cxts) {
+  XSH_ASSERT(xsh_loaded == 1);
+  ptable_loaded_free(xsh_loaded_cxts);
+  xsh_loaded_cxts = NULL;
+  xsh_loaded      = 0;
+  global_teardown = 1;
+ }
+
+ return global_teardown;
+}
+
+#else  /*  XSH_THREADS_COMPILE_TIME_PROTECTION */
+
+#define xsh_is_loaded_locked(C)    (xsh_loaded > 0)
+#define xsh_set_loaded_locked(C)   ((xsh_loaded++ <= 0) ? 1 : 0)
+#define xsh_clear_loaded_locked(C) ((--xsh_loaded <= 0) ? 1 : 0)
+
+#if XSH_THREADSAFE
+
+static int xsh_is_loaded(pTHX_ void *cxt) {
+#define xsh_is_loaded(C) xsh_is_loaded(aTHX_ (C))
+ int res = 0;
+
+ XSH_LOADED_LOCK;
+ res = xsh_is_loaded_locked(cxt);
+ XSH_LOADED_UNLOCK;
+
+ return res;
+}
+
+#else
+
+#define xsh_is_loaded(C) xsh_is_loaded_locked(C)
+
+#endif
+
+#endif /* !XSH_THREADS_COMPILE_TIME_PROTECTION */
+
+#define MY_CXT_KEY XSH_PACKAGE "::_guts" XS_VERSION
+
+typedef struct {
+#if XSH_THREADS_USER_CONTEXT
+ xsh_user_cxt_t  cxt_user;
+#endif
+#if XSH_THREADS_PEEP_CONTEXT
+ xsh_peep_cxt_t  cxt_peep;
+#endif
+#if XSH_THREADS_HINTS_CONTEXT
+ xsh_hints_cxt_t cxt_hints;
+#endif
+#if XSH_THREADS_CLONE_NEEDS_DUP
+ tTHX            owner;
+#endif
+#if !(XSH_THREADS_USER_CONTEXT || XSH_THREADS_PEEP_CONTEXT || XSH_THREADS_HINTS_CONTEXT || XSH_THREADS_CLONE_NEEDS_DUP)
+ int             dummy;
+#endif
+} my_cxt_t;
+
+START_MY_CXT
+
+#if XSH_THREADS_USER_CONTEXT
+# define dXSH_CXT dMY_CXT
+# define XSH_CXT  (MY_CXT.cxt_user)
+#endif
+
+#if XSH_THREADS_USER_GLOBAL_SETUP
+static void xsh_user_global_setup(pTHX);
+#endif
+
+#if XSH_THREADS_USER_LOCAL_SETUP
+# if XSH_THREADS_USER_CONTEXT
+static void xsh_user_local_setup(pTHX_ xsh_user_cxt_t *cxt);
+# else
+static void xsh_user_local_setup(pTHX);
+# endif
+#endif
+
+#if XSH_THREADS_USER_LOCAL_TEARDOWN
+# if XSH_THREADS_USER_CONTEXT
+static void xsh_user_local_teardown(pTHX_ xsh_user_cxt_t *cxt);
+# else
+static void xsh_user_local_teardown(pTHX);
+# endif
+#endif
+
+#if XSH_THREADS_USER_GLOBAL_TEARDOWN
+static void xsh_user_global_teardown(pTHX);
+#endif
+
+#if XSH_THREADSAFE && XSH_THREADS_USER_CONTEXT
+# if XSH_THREADS_USER_CLONE_NEEDS_DUP
+static void xsh_user_clone(pTHX_ const xsh_user_cxt_t *old_cxt, xsh_user_cxt_t *new_cxt, CLONE_PARAMS *params);
+# else
+static void xsh_user_clone(pTHX_ const xsh_user_cxt_t *old_cxt, xsh_user_cxt_t *new_cxt);
+# endif
+#endif
+
+#if XSH_THREADS_PEEP_CONTEXT
+static xsh_peep_cxt_t *xsh_peep_get_cxt(pTHX) {
+ dMY_CXT;
+ XSH_ASSERT(xsh_is_loaded(&MY_CXT));
+ return &MY_CXT.cxt_peep;
+}
+#endif
+
+#if XSH_THREADS_HINTS_CONTEXT
+static xsh_hints_cxt_t *xsh_hints_get_cxt(pTHX) {
+ dMY_CXT;
+ XSH_ASSERT(xsh_is_loaded(&MY_CXT));
+ return &MY_CXT.cxt_hints;
+}
+#endif
+
+#if XSH_THREADS_NEED_TEARDOWN_LATE
+
+typedef void (*xsh_teardown_late_cb)(pTHX_ void *ud);
+
+static int xsh_teardown_late_simple_free(pTHX_ SV *sv, MAGIC *mg) {
+ xsh_teardown_late_cb cb;
+
+ cb = DPTR2FPTR(xsh_teardown_late_cb, mg->mg_ptr);
+
+ XSH_LOADED_LOCK;
+ if (xsh_loaded == 0)
+  cb(aTHX_ NULL);
+ XSH_LOADED_UNLOCK;
+
+ return 0;
+}
+
+static MGVTBL xsh_teardown_late_simple_vtbl = {
+ 0,
+ 0,
+ 0,
+ 0,
+ xsh_teardown_late_simple_free
+#if MGf_COPY
+ , 0
+#endif
+#if MGf_DUP
+ , 0
+#endif
+#if MGf_LOCAL
+ , 0
+#endif
+};
+
+typedef struct {
+ xsh_teardown_late_cb  cb;
+ void                 *ud;
+} xsh_teardown_late_token;
+
+static int xsh_teardown_late_arg_free(pTHX_ SV *sv, MAGIC *mg) {
+ xsh_teardown_late_token *tok;
+
+ tok = (xsh_teardown_late_token *) mg->mg_ptr;
+
+ XSH_LOADED_LOCK;
+ if (xsh_loaded == 0)
+  tok->cb(aTHX_ tok->ud);
+ XSH_LOADED_UNLOCK;
+
+ PerlMemShared_free(tok);
+
+ return 0;
+}
+
+static MGVTBL xsh_teardown_late_arg_vtbl = {
+ 0,
+ 0,
+ 0,
+ 0,
+ xsh_teardown_late_arg_free
+#if MGf_COPY
+ , 0
+#endif
+#if MGf_DUP
+ , 0
+#endif
+#if MGf_LOCAL
+ , 0
+#endif
+};
+
+static void xsh_teardown_late_register(pTHX_ xsh_teardown_late_cb cb, void *ud){
+#define xsh_teardown_late_register(CB, UD) xsh_teardown_late_register(aTHX_ (CB), (UD))
+ void *ptr;
+
+ if (!ud) {
+  ptr = FPTR2DPTR(void *, cb);
+ } else {
+  xsh_teardown_late_token *tok;
+
+  tok     = PerlMemShared_malloc(sizeof *tok);
+  tok->cb = cb;
+  tok->ud = ud;
+
+  ptr = tok;
+ }
+
+ if (!PL_strtab)
+  PL_strtab = newHV();
+
+ sv_magicext((SV *) PL_strtab, NULL, PERL_MAGIC_ext,
+             ud ? &xsh_teardown_late_arg_vtbl : &xsh_teardown_late_simple_vtbl,
+             ptr, 0);
+
+ return;
+}
+
+#endif /* XSH_THREADS_NEED_TEARDOWN_LATE */
+
+static void xsh_teardown(pTHX_ void *root) {
+ dMY_CXT;
+
+#if XSH_THREADS_USER_LOCAL_TEARDOWN
+# if XSH_THREADS_USER_CONTEXT
+ xsh_user_local_teardown(aTHX_ &XSH_CXT);
+# else
+ xsh_user_local_teardown(aTHX);
+# endif
+#endif
+
+#if XSH_THREADS_PEEP_CONTEXT
+ xsh_peep_local_teardown(aTHX_ &MY_CXT.cxt_peep);
+#endif
+
+#if XSH_THREADS_HINTS_CONTEXT
+ xsh_hints_local_teardown(aTHX_ &MY_CXT.cxt_hints);
+#endif
+
+ XSH_LOADED_LOCK;
+
+ if (xsh_clear_loaded_locked(&MY_CXT)) {
+#if XSH_THREADS_USER_GLOBAL_TEARDOWN
+  xsh_user_global_teardown(aTHX);
+#endif
+
+#if XSH_THREADS_HINTS_CONTEXT
+  xsh_hints_global_teardown(aTHX);
+#endif
+ }
+
+ XSH_LOADED_UNLOCK;
+
+ return;
+}
+
+static void xsh_setup(pTHX) {
+#define xsh_setup() xsh_setup(aTHX)
+ MY_CXT_INIT; /* Takes/release PL_my_ctx_mutex */
+
+ XSH_LOADED_LOCK;
+
+ if (xsh_set_loaded_locked(&MY_CXT)) {
+#if XSH_THREADS_HINTS_CONTEXT
+  xsh_hints_global_setup(aTHX);
+#endif
+
+#if XSH_THREADS_USER_GLOBAL_SETUP
+  xsh_user_global_setup(aTHX);
+#endif
+ }
+
+ XSH_LOADED_UNLOCK;
+
+#if XSH_THREADS_CLONE_NEEDS_DUP
+ MY_CXT.owner = aTHX;
+#endif
+
+#if XSH_THREADS_HINTS_CONTEXT
+ xsh_hints_local_setup(aTHX_ &MY_CXT.cxt_hints);
+#endif
+
+#if XSH_THREADS_PEEP_CONTEXT
+ xsh_peep_local_setup(aTHX_ &MY_CXT.cxt_peep);
+#endif
+
+#if XSH_THREADS_USER_LOCAL_SETUP
+# if XSH_THREADS_USER_CONTEXT
+ xsh_user_local_setup(aTHX_ &XSH_CXT);
+# else
+ xsh_user_local_setup(aTHX);
+# endif
+#endif
+
+ call_atexit(xsh_teardown, NULL);
+
+ return;
+}
+
+#if XSH_THREADSAFE
+
+static void xsh_clone(pTHX) {
+#define xsh_clone() xsh_clone(aTHX)
+ const my_cxt_t *old_cxt;
+ my_cxt_t       *new_cxt;
+
+ {
+  dMY_CXT;
+  old_cxt = &MY_CXT;
+ }
+
+ {
+  int global_setup;
+
+  MY_CXT_CLONE;
+  new_cxt = &MY_CXT;
+
+  XSH_LOADED_LOCK;
+  global_setup = xsh_set_loaded_locked(new_cxt);
+  XSH_ASSERT(!global_setup);
+  XSH_LOADED_UNLOCK;
+
+#if XSH_THREADS_CLONE_NEEDS_DUP
+  new_cxt->owner = aTHX;
+#endif
+ }
+
+ {
+#if XSH_THREADS_CLONE_NEEDS_DUP
+  XSH_DUP_PARAMS_TYPE params;
+  xsh_dup_params_init(params, old_cxt->owner);
+#endif
+
+#if XSH_THREADS_PEEP_CONTEXT
+  xsh_peep_clone(aTHX_ &old_cxt->cxt_peep, &new_cxt->cxt_peep);
+#endif
+
+#if XSH_THREADS_HINTS_CONTEXT
+  xsh_hints_clone(aTHX_ &old_cxt->cxt_hints, &new_cxt->cxt_hints,
+                        xsh_dup_params_ptr(params));
+#endif
+
+#if XSH_THREADS_USER_CONTEXT
+# if XSH_THREADS_USER_CLONE_NEEDS_DUP
+  xsh_user_clone(aTHX_ &old_cxt->cxt_user, &new_cxt->cxt_user,
+                       xsh_dup_params_ptr(params));
+# else
+  xsh_user_clone(aTHX_ &old_cxt->cxt_user, &new_cxt->cxt_user);
+# endif
+#endif
+
+#if XSH_THREADS_CLONE_NEEDS_DUP
+  xsh_dup_params_deinit(params);
+#endif
+ }
+
+ return;
+}
+
+#endif /* XSH_THREADSAFE */
+
+#endif /* XSH_THREADS_H */
diff --git a/xsh/util.h b/xsh/util.h
new file mode 100644
index 0000000..dcc142c
--- /dev/null
+++ b/xsh/util.h
@@ -0,0 +1,97 @@
+#ifndef XSH_UTIL_H
+#define XSH_UTIL_H 1
+
+#include "caps.h" /* XSH_HAS_PERL() */
+
+#ifndef XSH_PACKAGE
+# error XSH_PACKAGE must be defined
+#endif
+
+#define XSH_PACKAGE_LEN (sizeof(XSH_PACKAGE)-1)
+
+#ifdef DEBUGGING
+# if XSH_HAS_PERL(5, 8, 9) || XSH_HAS_PERL(5, 9, 3)
+#  define XSH_ASSERT(C) assert(C)
+# else
+#  define XSH_ASSERT(C) PERL_DEB( \
+   ((C) ? ((void) 0)           \
+        : (Perl_croak_nocontext("Assertion %s failed: file \"" __FILE__  \
+                                 "\", line %d", STRINGIFY(C), __LINE__), \
+           (void) 0)))
+# endif
+#else
+# define XSH_ASSERT(C)
+#endif
+
+#undef VOID2
+#ifdef __cplusplus
+# define VOID2(T, P) static_cast<T>(P)
+#else
+# define VOID2(T, P) (P)
+#endif
+
+#ifndef STMT_START
+# define STMT_START do
+#endif
+
+#ifndef STMT_END
+# define STMT_END while (0)
+#endif
+
+#ifndef dNOOP
+# define dNOOP
+#endif
+
+#ifndef NOOP
+# define NOOP
+#endif
+
+#if XSH_HAS_PERL(5, 13, 2)
+# define XSH_DUP_PARAMS_TYPE       CLONE_PARAMS *
+# define xsh_dup_params_init(P, O) ((P) = Perl_clone_params_new((O), aTHX))
+# define xsh_dup_params_deinit(P)  Perl_clone_params_del(P)
+# define xsh_dup_params_ptr(P)     (P)
+#else
+# define XSH_DUP_PARAMS_TYPE       CLONE_PARAMS
+# define xsh_dup_params_init(P, O) \
+      ((P).stashes = newAV()); (P).flags = 0; ((P).proto_perl = (O))
+# define xsh_dup_params_deinit(P)  SvREFCNT_dec((P).stashes)
+# define xsh_dup_params_ptr(P)     &(P)
+#endif
+#define xsh_dup(S, P)     sv_dup((S), (P))
+#define xsh_dup_inc(S, P) SvREFCNT_inc(xsh_dup((S), (P)))
+
+/* Context for PerlMemShared_*() functions */
+#ifdef PERL_IMPLICIT_SYS
+# define pPMS  pTHX
+# define pPMS_ pTHX_
+# define aPMS  aTHX
+# define aPMS_ aTHX_
+#else
+# define pPMS  void
+# define pPMS_
+# define aPMS
+# define aPMS_
+#endif
+
+#ifdef USE_ITHREADS
+# define XSH_LOCK(M)   MUTEX_LOCK(M)
+# define XSH_UNLOCK(M) MUTEX_UNLOCK(M)
+#else
+# define XSH_LOCK(M)   NOOP
+# define XSH_UNLOCK(M) NOOP
+#endif
+
+#ifndef PTR2nat
+# define PTR2nat(p) (PTRV)(p)
+#endif
+
+#ifndef DPTR2FPTR
+# define DPTR2FPTR(t,p) ((t)PTR2nat(p))
+#endif
+
+#ifndef FPTR2DPTR
+# define FPTR2DPTR(t,p) ((t)PTR2nat(p))
+#endif
+
+#endif /* XSH_UTIL_H */