m3core/src/runtime/POSIX/RT0u.i3

 Copyright (C) 1990, Digital Equipment Corporation           
 All rights reserved.                                        
 See the file COPYRIGHT for a full description.              


 Last modified on Thu Jul 14 11:29:36 PDT 1994 by kalsow     


 RT0u is almost the bottom of the world.  It contains
   variables that are shared by multiple modules of the runtime
   and/or the compiler and linker.


   If you're using this interface, you're a wizard!


   This interface and its implemenation MUST NOT import any
   interface other than RT0.



UNSAFE INTERFACE RT0u;

------------------------------------------------------ mutual exclusion ---


<*EXTERNAL RT0u__inCritical*>
VAR inCritical: INTEGER;

 inCritical provides low-level mutual exclusion between the thread
   runtime, garbage collector and the Unix signal that triggers thread
   preemption.  If inCritical is greater than zero, thread preemption
   is disabled.  We *ASSUME* that INC(inCritical) and DEC(inCritical)
   generate code that is atomic with respect to Unix signal delivery. 

END RT0u.