Introduce VMG_FORKSAFE

[perl/modules/Variable-Magic.git] / Magic.xs

diff --git a/Magic.xs b/Magic.xs
index 218819f909fe653162f5c6bfec622cea11d9f3ea..1dada023c031867f619d812dc50bdc76facc7a78 100644 (file)
--- a/Magic.xs
+++ b/Magic.xs
@@ -36,6 +36,11 @@
 # define dNOOP
 #endif
 
+/* Safe unless stated otherwise in Makefile.PL */
+#ifndef VMG_FORKSAFE
+# define VMG_FORKSAFE 1
+#endif
+
 #ifndef VMG_MULTIPLICITY
 # if defined(MULTIPLICITY) || defined(PERL_IMPLICIT_CONTEXT)
 #  define VMG_MULTIPLICITY 1
@@ -135,8 +140,9 @@ STATIC SV *vmg_clone(pTHX_ SV *sv, tTHX owner) {
 # endif
 #endif
 
-/* uvar magic and Hash::Util::FieldHash were commited with 28419 */
-#if VMG_HAS_PERL_MAINT(5, 9, 4, 28419) || VMG_HAS_PERL(5, 10, 0)
+/* uvar magic and Hash::Util::FieldHash were commited with 28419, but only
+ * enable it on 5.10 */
+#if VMG_HAS_PERL(5, 10, 0)
 # define VMG_UVAR 1
 #else
 # define VMG_UVAR 0
@@ -812,7 +818,7 @@ STATIC int vmg_svt_clear(pTHX_ SV *sv, MAGIC *mg) {
 
 STATIC int vmg_svt_free(pTHX_ SV *sv, MAGIC *mg) {
  const MGWIZ *w;
-#if VMG_HAS_PERL(5, 10, 0)
+#if VMG_HAS_PERL(5, 9, 5)
  PERL_CONTEXT saved_cx;
  I32 cxix;
 #endif
@@ -853,7 +859,7 @@ STATIC int vmg_svt_free(pTHX_ SV *sv, MAGIC *mg) {
  if (had_err)
   flags |= G_KEEPERR;
 
-#if VMG_HAS_PERL(5, 10, 0)
+#if VMG_HAS_PERL(5, 9, 5)
  /* This context should not be used anymore, but since we croak in places the
   * core doesn't even dare to, some pointers to it may remain in the upper call
   * stack. Make sure call_sv() doesn't clobber it. */
@@ -866,7 +872,7 @@ STATIC int vmg_svt_free(pTHX_ SV *sv, MAGIC *mg) {
 
  call_sv(w->cb_free, flags);
 
-#if VMG_HAS_PERL(5, 10, 0)
+#if VMG_HAS_PERL(5, 9, 5)
  cxstack[cxix] = saved_cx;
 #endif
 
@@ -1262,6 +1268,7 @@ BOOT:
                     newSVuv(VMG_COMPAT_SCALAR_LENGTH_NOLEN));
  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_OP_INFO_NAME",    newSVuv(VMG_OP_INFO_NAME));
  newCONSTSUB(stash, "VMG_OP_INFO_OBJECT",  newSVuv(VMG_OP_INFO_OBJECT));
 }
@@ -1467,7 +1474,7 @@ PPCODE:
  sig  = vmg_wizard_sig(wiz);
  data = vmg_data_get(SvRV(sv), sig);
  if (!data)
-  XSRETURN_UNDEF;
+  XSRETURN_EMPTY;
  ST(0) = data;
  XSRETURN(1);