Re: Stack based allocation vs. Dynamic allocation

[Laurent Guerby <guerby@acm.org>]

Dale Stanbrough <dale@cs.rmit.edu.au> writes:
> I've fixed the code, and added in a few extras. I have compared various
> variations of the code (in C and in Ada), the results follow... [...]

Note that the Ada versions is not really comparable with the C version
since you have array bound safety in Ada (I guess the compiler removed
the checks) and not in C.

I'm surprised the Ada heap version is faster than the C one since GNAT
calls the system malloc (hmmm it might be a GNU malloc vs Solaris
malloc issue if you're using FSU threads).

Also you can have more fun by having the size of the local array
variable being a function of i, since there is no C stack based
equivalent (GNU C has it as a language extension though).

The only problem with stack based allocation is in a 32 bits address
space multi threaded application context where you might have big
arrays, you have then an unsolvable problem with thread stack size.

On the software I'm working on, we had to move some stack based
(dynamic) array to the heap (with controlled types for automatic
deallocation) for this reason.

-- 
Laurent Guerby <guerby@acm.org>