diff -up wvstreams-4.6.1/include/wvtask.h.magic wvstreams-4.6.1/include/wvtask.h
--- wvstreams-4.6.1/include/wvtask.h.magic	2008-07-14 21:11:35.000000000 +0200
+++ wvstreams-4.6.1/include/wvtask.h	2012-06-03 17:24:47.909187849 +0200
@@ -45,7 +45,8 @@ class WvTask
     typedef void TaskFunc(void *userdata);
     
     static int taskcount, numtasks, numrunning;
-    int magic_number, *stack_magic;
+    int volatile magic_number;
+    int *stack_magic;
     WvString name;
     int tid;
     
@@ -84,7 +85,7 @@ class WvTaskMan
     static WvTaskMan *singleton;
     static int links;
     
-    static int magic_number;
+    static int volatile magic_number;
     static WvTaskList all_tasks, free_tasks;
     
     static void get_stack(WvTask &task, size_t size);
diff -up wvstreams-4.6.1/utils/wvtask.cc.magic wvstreams-4.6.1/utils/wvtask.cc
--- wvstreams-4.6.1/utils/wvtask.cc.magic	2009-05-13 23:42:52.000000000 +0200
+++ wvstreams-4.6.1/utils/wvtask.cc	2012-06-03 14:29:09.729656804 +0200
@@ -58,7 +58,8 @@ char *alloca ();
 int WvTask::taskcount, WvTask::numtasks, WvTask::numrunning;
 
 WvTaskMan *WvTaskMan::singleton;
-int WvTaskMan::links, WvTaskMan::magic_number;
+int WvTaskMan::links;
+int volatile WvTaskMan::magic_number;
 WvTaskList WvTaskMan::all_tasks, WvTaskMan::free_tasks;
 ucontext_t WvTaskMan::stackmaster_task, WvTaskMan::get_stack_return,
     WvTaskMan::toplevel;