Index: apc_string.c
===================================================================
--- apc_string.c	(revision 313617)
+++ apc_string.c	(working copy)
@@ -49,6 +49,7 @@
 static char *old_interned_strings_start;
 static char *old_interned_strings_end;
 static const char *(*old_new_interned_string)(const char *str, int len, int free_src TSRMLS_DC);
+static zend_bool (*old_is_interned_string)(const char *str TSRMLS_DC);
 static void (*old_interned_strings_snapshot)(TSRMLS_D);
 static void (*old_interned_strings_restore)(TSRMLS_D);
 
@@ -126,6 +127,20 @@
     return p->arKey;
 }
 
+static zend_bool apc_is_interned_string(const char* s TSRMLS_DC)
+{
+    if((s >= APCSG(interned_strings_start)) && 
+            s < APCSG(interned_strings_end)) {
+        return 1;
+    }
+
+    if(old_is_interned_string) {
+        return old_is_interned_string(s TSRMLS_CC);
+    }
+
+    return 0;
+}
+
 static void apc_copy_internal_strings(TSRMLS_D)
 {
     Bucket *p, *q;
@@ -205,17 +220,15 @@
     APCSG(interned_strings_end)   = (char*)apc_interned_strings_data + APCG(shm_strings_buffer);
     APCSG(interned_strings_top)   = APCSG(interned_strings_start);
 
-    old_interned_strings_start = CG(interned_strings_start);
-    old_interned_strings_end = CG(interned_strings_end);
     old_new_interned_string = zend_new_interned_string;
+    old_is_interned_string = zend_is_interned_string;
     old_interned_strings_snapshot = zend_interned_strings_snapshot;
     old_interned_strings_restore = zend_interned_strings_restore;
 
-    CG(interned_strings_start) = APCSG(interned_strings_start);
-    CG(interned_strings_end) = APCSG(interned_strings_end);
     zend_new_interned_string = apc_dummy_new_interned_string_for_php;
     zend_interned_strings_snapshot = apc_dummy_interned_strings_snapshot_for_php;
     zend_interned_strings_restore = apc_dummy_interned_strings_restore_for_php;
+    zend_is_interned_string = apc_is_interned_string;
 
     apc_copy_internal_strings(TSRMLS_C);
 }
@@ -226,9 +239,8 @@
     zend_hash_clean(CG(class_table));
     zend_hash_clean(EG(zend_constants));
 
-    CG(interned_strings_start) = old_interned_strings_start;
-    CG(interned_strings_end) = old_interned_strings_end;
     zend_new_interned_string = old_new_interned_string;
+    zend_is_interned_string = old_is_interned_string;
     zend_interned_strings_snapshot = old_interned_strings_snapshot;
     zend_interned_strings_restore = old_interned_strings_restore;