🚀 go-pugleaf

In <1992Dec17.160015.24323@mksol.dseg.ti.com> duitz@mksol.dseg.ti.com (mitchel n duitz) writes:

>I'm using The Large Model in the program, and the allocation
>works fine the first time I use the object, then when i delete
>the object that uses all the memory, and try again it bombs.
>I am freeing the memory delete[] pn.   So I don;t know
>what's going on.  I even looped through with the debugger, and
>then it got to a magic row and it locked up. Thanks.

So, it sounds like the problem isn't in the allocation (because it works the
first time) but the de-allocation.  My understanding is that the construct
"delete [] pn" is used for freeing the memory allocated with something like
"int *pn = new int[100]".  But if you're allocating memory for an array of
pointers and then do subsequent allocations for arrays for the individual
pointers in the first array to point to, don't you have to do something
like:

    for (int i = 0; i < MAXX; i++)
	delete [] pn[i];
    delete [] pn;

I personally find this sort of confusing, but it that seems like it should 
work.  I don't know why "delete [] pn" by itself doesn't work (I could
see it not freeing the bulk of the data, and destroying the pointers to
a lot of data, but I don't see why that would be fatal).  Perhaps when
you're doing the next loop, the system runs out of memory, does a garbage
collection (of sorts), but since the pointers for some unallocated data
have been destroyed, it gets confused.  Ideas?

I really don't know and am just guessing, but does that make sense?  Have
I gone seriously awry here?

-- 
 Rob Ryan
    rryan@panix.com