On Wed, Aug 31, 2005 at 11:13:00AM +0200, Miguel A. Nu?ez wrote: > > > ILT> Bob Rossi <bob@xxxxxxxxxx> writes: > > >> On Tue, Aug 30, 2005 at 10:54:02PM +0100, Lexington Luthor wrote: > >> > >> > I think for large arrays, its best to allocate them from the heap. Use > >> > malloc() or new (if using C++). > >> > >> I've always been told that the heap and stack grow towards each other. > >> If this is true, why would it be OK to create the item on the heap, vs > >> on the stack? If it's not true, could someone simply explain how this > >> works? > > ILT> You are correct in theory. In practice the heap and stack have > ILT> different limits, and the limit on the heap is much larger than the > ILT> stack (if running bash, compare ulimit -s and ulimit -v). And if you > ILT> worry about portability, on some platforms allocating a large stack > ILT> frame will simply fail, and on some other platforms it will require > ILT> extra work to emit stack probes to tell the OS that you are > ILT> intentionally extending the stack rather than just referencing a > ILT> random memory address. > > ILT> Ian > > > Ian, > > I did ulimit -s and ulimit -v in a solaris 9 sun machine. ulimit -s returns 8192, ok, but ulimit -s returns unlimited. Does this make sense? Assumming you mean ulimit -s = 8192 and ulimit -v = unlimited, then yes, I suppose that makes sense. On my linux machine, ulimit -s and ulimit -v = unlimited. In this case, I suppose it's possible that if the array was on the stack and things borked, it would also bork when on the heap. However, in your case, I know understand why things would work for you if you moved from the stack to the heap. Bob Rossi
