Are there any common lisp implementation that allow modifying the stack size at run-time? What about the size of the heap?
I am using sbcl and apparently these are defined when the executable is started, and cannot be altered afterwards.
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What are you aiming to accomplish with this? The fact that you're fiddling with the stack dynamically is a bit odddaniel gratzer– daniel gratzer2013-08-11 04:40:43 +00:00Commented Aug 11, 2013 at 4:40
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1 Answer
For example ECL and LispWorks can extend the stack at runtime. One can see that both are also offering restarts when there is a stack overflow, to increase the stack size, if necessary:
ECL:
> (defun s (n)
(if (zerop n) 0 (+ 1 (s (1- n)))))
S
> (s 100000)
Condition of type: STACK-OVERFLOW
C-STACK overflow at size 4259840. Stack can probably be resized.
Available restarts:
1. (CONTINUE) Extend stack size
2. (RESTART-TOPLEVEL) Go back to Top-Level REPL.
Broken at S. In: #<process TOP-LEVEL>.
>>
See the ECL memory management documentation at: http://ecls.sourceforge.net/new-manual/re86.html
LispWorks:
CL-USER 31 > (s 1000)
Stack overflow (stack size 15997).
1 (continue) Extend stack by 50%.
2 Extend stack by 300%.
3 (abort) Return to level 0.
4 Return to top loop level 0.
Type :b for backtrace or :c <option number> to proceed.
Type :bug-form "<subject>" for a bug report template or :? for other options.
A variable in LispWorks allows customization: SYSTEM:*STACK-OVERFLOW-BEHAVIOUR*. See http://www.lispworks.com/documentation/lw61/LW/html/lw-1440.htm#marker-887330 .
The heap grows automatically in most implementations by requesting more memory from the operating system. The next question then would be: can the heap shrink?
2 Comments
stackman
What about ccl? Out of curiosity, would it be hard to implement a dynamically resizable stack in sbcl?
Rainer Joswig
@stackman: In CCL you can set the stack size of thread, if you start a new one. How hard is in to implement in SBCL? I have no idea. You would have to ask the implementors.