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From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: Dinamic array without malloc - Can be done?
Date: Mon, 16 Jan 2017 09:22:05 -0800
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David Brown <david.brown@hesbynett.no> writes:
[...]
> IMHO, alloca and VLA are no worse than many other things in C - you
> simply have to know what you are doing and be sure you are doing things
> properly, such as checking the size before allocation.
[...]

I agree, mostly.  But alloca and VLAs make it easier (relative to
fixed-size arrays) to overflow the stack by accidentally allocating a
very large chunk of memory.  Given:

    {
        size_t n = some_computation;
        double vla[n];
    }

it can be arbitrarily difficult to avoid overflow, and to perform static
analysis of how much the stack can grow.

The solution, as with most things, is "be careful".

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"