-/* Calls pthread_atfork() if present, and else does nothing.
- * The only known user of this wrapper is mmalloc_preinit(); This function may disapear in the near future.
+/** Calls pthread_atfork() if present, and raise an exception otherwise.
+ *
+ * The only known user of this wrapper is mmalloc_preinit(), but it is absolutely mandatory there:
+ * when used with tesh, mmalloc *must* be mutex protected and resistant to forks.
+ * This functionality is the only way to get it working (by ensuring that the mutex is consistently released on forks)