fibre.cr

require "thread"

puts Thread.current.current_fiber.inspect

Thread.new { puts Thread.current.current_fiber.inspect }.join

gistfile1.txt

$ crystal -v
Crystal 0.19.2 (2016-09-16)

$ crystal fibre.cr 
#<Fiber:0x10dcb7f50: main>
Invalid memory access (signal 11) at address 0x48
[4522891179] *CallStack::print_backtrace:Int32 +107
[4522880391] __crystal_sigfault_handler +55
[140735729448234] _sigtramp +26
[4522886092] *Fiber#to_s<String::Builder>:String::Builder +92
[4522885993] *Fiber#inspect<String::Builder>:String::Builder +9
[4522885954] *Fiber@Object#inspect:String +66
[4522880546] ~procProc(Nil)@./fibre.cr:5 +18
[4522887057] *Thread#start:(Exception+ | Nil) +65
[4522880521] ~procProc(Pointer(Void), (Exception | Nil))@/usr/local/Cellar/crystal-lang/0.19.2/src/thread.cr:19 +9
[4523388330] GC_inner_start_routine +90
[4523372168] GC_call_with_stack_base +27
[140735840500125] _pthread_body +131
[140735840499994] _pthread_start +168