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From: Ken Keys <klkeys@west.raytheon.com>
Subject: Re: Dynamic memory? (was Re: Ada vs C++ vs Java)
Date: 1999/01/18
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Date: 1999-01-18T00:00:00+00:00
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John Birch wrote:

> In C the stack size can never be larger the maximum of the total of
> the stack requirements of all of the functions defined.

And the heap requirements can never be larger than the maximum of the
total of the heap requirements of all of the functions defined. Indeed
in that case even fragmentation is not an issue because you can assume
that memory is never freed and just add up all the allocations.


> Now try telling me how to calculate a worst case C++ memory
> requirement.

I don't see how the equation would be any different in C++ than in C
except that there is a tendency to use the heap more in C++. 

In C it is considered bad form to allocate really big data structures on
the stack but there is nothing in the language that prevents it. If you
limit the stack usage to the most benign objects and put the big stuff
on the heap, it makes your worst case stack look better. 

The only problem is that if you extend the analysis to all types of
memory allocations and you use some big objects, your worst case figure
can be much larger than what the system would reasonably need. 

KLK