# 1.9 tail-call optimization status?

**URL:** <https://www.ruby-forum.com/t/1-9-tail-call-optimization-status/146623>\
**Category:** Ruby\
**Created:** [August 23, 2008, 6:39am UTC](https://www.ruby-forum.com/t/1-9-tail-call-optimization-status/146623 "2008-08-23T06:39:49Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![samoht](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ac8455/32.png) [@samoht](https://www.ruby-forum.com/u/samoht)\
**Post date:** [August 23, 2008, 6:39am UTC](https://www.ruby-forum.com/t/1-9-tail-call-optimization-status/146623/1 "2008-08-23T06:39:49Z")

</div>

vm\_opts.h contains:

#define OPT\_TAILCALL\_OPTIMIZATION 0

In an interview, ko1 mentioned it should be enabled in 1.9’s release,  
and needed testing:

[Gray Soft / Not Found](http://blog.grayproductions.net/articles/the_ruby_vm_episode_v)

Current Ruby 1.9 (trunk) is not enabled this optimization. If you want  
to try this, please re-write that option in “vm\_opts.h”  
(OPT\_TAILCALL\_OPTIMIZATION) and re-compile that. I think release  
version of Ruby 1.9 is enabled this optimization. I need more comments  
of it

That was a year ago, and I’ve not noticed much else in the way of  
references to it. Is anyone aware of it’s current status? It seems to  
work, but I can’t say I’ve tested it significantly.