+/* This call must be previously enabled (see above). */
+/* This should never be called from the main thread, where it is */
+/* always done implicitly. This is normally done implicitly if GC_ */
+/* functions are called to create the thread, e.g. by defining */
+/* GC_THREADS and including gc.h (which redefines some system */
+/* functions) before calling the system thread creation function. */
+/* It is also always done implicitly under win32 with DllMain-based */
+/* thread registration enabled. Except in this latter case, explicit */
+/* calls are normally required for threads created by third-party */
+/* libraries. */