--- Coro-Multicore/Multicore.xs	2015/12/19 23:56:35	1.15
+++ Coro-Multicore/Multicore.xs	2016/01/24 04:20:49	1.16
@@ -24,7 +24,13 @@
   #define SvREFCNT_inc_NN(sv) SvREFCNT_inc (sv)
 #endif
 
+#define RECURSION_CHECK 0
+
 static X_TLS_DECLARE(current_key);
+#if RECURSION_CHECK
+static X_TLS_DECLARE(check_key);
+#endif
+
 
 static s_epipe ep;
 static void *perl_thx;
@@ -175,6 +181,13 @@
 static void
 pmapi_release (void)
 {
+  #if RECURSION_CHECK
+  if (X_TLS_GET (check_key))
+    croak ("perlinterp_release () called without valid perl context");
+
+  X_TLS_SET (check_key, &check_key);
+  #endif
+
   if (! ((thread_enable ? thread_enable : global_enable) & 1))
     {
       X_TLS_SET (current_key, 0);
@@ -211,6 +224,13 @@
   int jeret;
   struct tctx *ctx = X_TLS_GET (current_key);
 
+  #if RECURSION_CHECK
+  if (X_TLS_GET (check_key) != &check_key)
+    croak ("perlinterp_acquire () called with valid perl context");
+
+  X_TLS_SET (check_key, 0);
+  #endif
+
   if (!ctx)
     return;
 
@@ -243,11 +263,14 @@
 
 BOOT:
 {
-	#ifndef _WIN32
+#ifndef _WIN32
 	sigfillset (&fullsigset);
-	#endif
+#endif
 
         X_TLS_INIT (current_key);
+#if RECURSION_CHECK
+        X_TLS_INIT (check_key);
+#endif
 
         if (s_epipe_new (&ep))
           croak ("Coro::Multicore: unable to initialise event pipe.\n");