* vm.c (ruby_vm_at_exit): new API. This enables extension libs to

	  hook a VM termination.  Right now, because the VM we have is
	  process global, most extensions do not deallocate resources and
	  leave them to Operating System's reaping userland processes.  But
	  in a future we plan to have multiple VMs to run simultaneously in
	  a single process (MVM project).  At that stage we can no longer
	  rely on OSes and have to manage every resources to be reclaimed
	  properly.  So it is.  For a forward-compatibility reason this API
	  is introduced now, encouraging you to be as gentle as you can for
	  your resources; that is, tidy up your room.

	* include/ruby/vm.h: ditto.

	* vm_core.h (rb_vm_struct): new field.

	* vm.c (vm_init2): initialize above new field.

	* eval.c (ruby_cleanup): trigger those hooks.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@30050 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 18 insertions, 0 deletions

diff --git a/include/ruby/vm.h b/include/ruby/vm.h
index 072d7d6f19..1146bf5426 100644
--- a/include/ruby/vm.h
+++ b/include/ruby/vm.h
@@ -36,6 +36,24 @@ typedef struct rb_vm_struct ruby_vm_t;
 /* core API */
 int ruby_vm_destruct(ruby_vm_t *vm);
 
+/**
+ * ruby_vm_at_exit registers a function _func_ to be invoked when a VM
+ * passed away.  Functions registered this way runs in reverse order
+ * of registration, just like END {} block does.  The difference is
+ * its timing to be triggered. ruby_vm_at_exit functions runs when a
+ * VM _passed_ _away_, while END {} blocks runs just _before_ a VM
+ * _is_ _passing_ _away_.
+ *
+ * You cannot register a function to another VM than where you are in.
+ * So where to register is intuitive, omitted.  OTOH the argument
+ * _func_ cannot know which VM it is in because at the time of
+ * invocation, the VM has already died and there is no execution
+ * context.  The VM itself is passed as the first argument to it.
+ *
+ * @param[in] func the function to register.
+ */
+void ruby_vm_at_exit(void(*func)(ruby_vm_t *));
+
 #if defined __GNUC__ && __GNUC__ >= 4
 #pragma GCC visibility pop
 #endif