When I run the following code:
(defun countdown (n)
(if (>= n 0)
(cons n (countdown (- n 1)))))
(countdown 100000)
I get the following message :
INFO: Control stack guard page unprotected
Control stack guard page temporarily disabled: proceed with caution
debugger invoked on a SB-KERNEL::CONTROL-STACK-EXHAUSTED in thread
#<THREAD "main thread" RUNNING {1002B03653}>:
Control stack exhausted (no more space for function call frames).
This is probably due to heavily nested or infinitely recursive function
calls, or a tail call that SBCL cannot or has not optimized away.
PROCEED WITH CAUTION.
Type HELP for debugger help, or (SB-EXT:EXIT) to exit from SBCL.
restarts (invokable by number or by possibly-abbreviated name):
0: [ABORT] Exit debugger, returning to top level.
(SB-KERNEL::CONTROL-STACK-EXHAUSTED-ERROR)
How do I increase the stack space? I do not want to change the code above; I supplied it purely to illustrate stack exhaustion.
Calling sbcl with the --help option on the command line gives some useful common options, including an option for how to increase the stack space. You want to to use the --control-stack-size argument.
$ sbcl --help
Usage: sbcl [runtime-options] [toplevel-options] [user-options]
Common runtime options:
--help Print this message and exit.
--version Print version information and exit.
--core <filename> Use the specified core file instead of the default.
--dynamic-space-size <MiB> Size of reserved dynamic space in megabytes.
--control-stack-size <MiB> Size of reserved control stack in megabytes.
...
By specifying a bigger value there, we can run your code:
$ sbcl --control-stack-size 100000
* (defun countdown (n)
(if (>= n 0)
(cons n (countdown (- n 1)))))
;=> (100000 … 6 5 4 3 2 1 0)