On 2015/01/13 3:23, jared / jaredbeck.com wrote: > ~~~ > ruby --version > ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin13.0] > > echo 'puts RUBY_VM_FIBER_VM_STACK_SIZE' | ruby > -:1:in `<main>': uninitialized constant RUBY_VM_FIBER_VM_STACK_SIZE (NameError) > > echo 'puts RUBY_FIBER_MACHINE_STACK_SIZE' | ruby > -:1:in `<main>': uninitialized constant RUBY_FIBER_MACHINE_STACK_SIZE (NameError) > ~~~ They are environment variables.