## code
t = Thread.new { p 5 }
t.join

## gdb
$ gdb vm/vm
GNU gdb 6.6
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "x86_64-pc-linux-gnu"...
Using host libthread_db library "/lib/libthread_db.so.1".
(gdb) r thread.rb
Starting program: /home/brixen/rubuildius/repo/rubinius/e4c7d3a74ea8b6ed39529fc3b5affa988495cd32/vm/vm thread.rb
[Thread debugging using libthread_db enabled]
[New Thread 47569272873344 (LWP 9472)]
[New Thread 1082132800 (LWP 9475)]
5

Program received signal SIGINT, Interrupt.
[Switching to Thread 47569272873344 (LWP 9472)]
0x00002b4395843356 in poll () from /lib/libc.so.6
(gdb) b rubinius::VM::find_and_activade_thread
the class rubinius::VM does not have any method named find_and_activade_thread
Hint: try 'rubinius::VM::find_and_activade_thread<TAB> or 'rubinius::VM::find_and_activade_thread<ESC-?>
(Note leading single quote.)
(gdb) b rubinius::VM::find_and_activate_thread
Breakpoint 1 at 0x5a47e0: file vm/vm.cpp, line 219.
(gdb) c
Continuing.

Breakpoint 1, rubinius::VM::find_and_activate_thread (this=0x7fff15cf81d0) at vm/vm.cpp:219
219       bool VM::find_and_activate_thread() {
(gdb) n
220         Tuple* scheduled = globals.scheduled_threads.get();
(gdb) n
222         for(std::size_t i = scheduled->num_fields() - 1; i > 0; i--) {
(gdb)
223           List* list = as<List>(scheduled->at(this, i));
(gdb) p i
$1 = 2
(gdb) n
225           Thread* thread = try_as<Thread>(list->shift(this));
(gdb)
227           while(thread) {
(gdb)
222         for(std::size_t i = scheduled->num_fields() - 1; i > 0; i--) {
(gdb)
223           List* list = as<List>(scheduled->at(this, i));
(gdb)
225           Thread* thread = try_as<Thread>(list->shift(this));
(gdb)
227           while(thread) {
(gdb)
222         for(std::size_t i = scheduled->num_fields() - 1; i > 0; i--) {
(gdb)
246         return false;
(gdb) c
Continuing.