Merge 'get-restart-signal-feature' branch

AUTHORS

@@ -139,6 +139,7 @@ Jacob Navia
 Jakub Jelinek
 James Clark <jjc@jclark.com>
 James Dominy
+Jan Wielemaker <J.Wielemaker@cs.vu.nl>
 Jani Kajala
 Jean-Baptiste Nivois
 Jean-Claude Beaudoin <jean.claude.beaudoin@gmail.com>

ChangeLog

@@ -3,6 +3,7 @@
 =========================
 
 * Add GC_UNDERSCORE_STDCALL, UNICODE macro templates to configure (Win32).
+* Add GC_get_thr_restart_signal API entry.
 * Add GC_move_disappearing_link() API entry.
 * Add TODO file.
 * Add configure option to compile all library .c files into single gc.o.

include/gc.h

@@ -1082,6 +1082,10 @@ GC_API void * GC_CALL GC_call_with_stack_base(GC_stack_base_func /* fn */,
   /* to suspend threads on POSIX systems.  Return -1 otherwise.         */
   GC_API int GC_CALL GC_get_suspend_signal(void);
 
+  /* Return the signal number (constant) used by the garbage collector  */
+  /* to restart (resume) threads on POSIX systems. Return -1 otherwise. */
+  GC_API int GC_CALL GC_get_thr_restart_signal(void);
+
   /* Explicitly enable GC_register_my_thread() invocation.              */
   /* Done implicitly if a GC thread-creation function is called (or     */
   /* implicit thread registration is activated).  Otherwise, it must    */

misc.c

@@ -467,6 +467,13 @@ GC_API void GC_CALL GC_get_heap_usage_safe(GC_word *pheap_size,
       return -1;
 #   endif
   }
+
+# if defined(GC_DARWIN_THREADS) || defined(GC_WIN32_THREADS)
+    GC_API int GC_CALL GC_get_thr_restart_signal(void)
+    {
+      return -1; /* GC does not use signals to restart threads. */
+    }
+# endif
 #endif /* THREADS */
 
 #ifdef GC_READ_ENV_FILE

pthread_stop_world.c

@@ -872,4 +872,13 @@ GC_INNER void GC_stop_init(void)
 # endif /* !GC_OPENBSD_THREADS && !NACL */
 }
 
+  GC_API int GC_CALL GC_get_thr_restart_signal(void)
+  {
+#   if !defined(GC_OPENBSD_THREADS) && !defined(NACL)
+      return SIG_THR_RESTART;
+#   else
+      return -1;
+#   endif
+  }
+
 #endif