nobu	2018-08-17 10:39:49 +0900 (Fri, 17 Aug 2018)

  New Revision: 64402

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=64402

  Log:
    signal.c: no SIGCHLD, no sigchld_hit
    
    * signal.c (sigchld_hit): if SIGCHLD is not available, this variable
      never sets.

  Modified files:
    trunk/signal.c
Index: signal.c
===================================================================
--- signal.c	(revision 64401)
+++ signal.c	(revision 64402)
@@ -707,7 +707,13 @@ signal_enque(int sig) https://github.com/ruby/ruby/blob/trunk/signal.c#L707
     ATOMIC_INC(signal_buff.size);
 }
 
+#if RUBY_SIGCHLD
 static rb_atomic_t sigchld_hit;
+/* destructive getter than simple predicate */
+# define GET_SIGCHLD_HIT() ATOMIC_EXCHANGE(sigchld_hit, 0)
+#else
+# define GET_SIGCHLD_HIT() 0
+#endif
 
 static RETSIGTYPE
 sighandler(int sig)
@@ -716,6 +722,7 @@ sighandler(int sig) https://github.com/ruby/ruby/blob/trunk/signal.c#L722
 
     /* the VM always needs to handle SIGCHLD for rb_waitpid */
     if (sig == RUBY_SIGCHLD) {
+#if RUBY_SIGCHLD
         rb_vm_t *vm = GET_VM();
         ATOMIC_EXCHANGE(sigchld_hit, 1);
 
@@ -723,6 +730,7 @@ sighandler(int sig) https://github.com/ruby/ruby/blob/trunk/signal.c#L730
         if (vm && ACCESS_ONCE(VALUE, vm->trap_list.cmd[sig])) {
             signal_enque(sig);
         }
+#endif
     }
     else {
         signal_enque(sig);
@@ -1076,7 +1084,7 @@ void ruby_waitpid_all(rb_vm_t *); /* pro https://github.com/ruby/ruby/blob/trunk/signal.c#L1084
 void
 ruby_sigchld_handler(rb_vm_t *vm)
 {
-    if (SIGCHLD_LOSSY || ATOMIC_EXCHANGE(sigchld_hit, 0)) {
+    if (SIGCHLD_LOSSY || GET_SIGCHLD_HIT()) {
         ruby_waitpid_all(vm);
     }
 }

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