Date: Wed, 14 Sep 2016 15:56:49 +0000 From: twilight <pipfstarrd@openmailbox.org> To: freebsd-hackers@freebsd.org Subject: Re: Is replacing alloca(3) where possible a good thing to do? Message-ID: <f71ce065-0994-9deb-2457-544f90a26105@openmailbox.org> In-Reply-To: <bd0607f1-2224-02db-e430-6c34e42297bf@freebsd.org> References: <d192dbeb-5647-e552-9db1-b478aa7ac057@FreeBSD.org> <bd0607f1-2224-02db-e430-6c34e42297bf@freebsd.org>
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> The one time I tried to use it, it went very badly, as it returns a > pointer, but the actual amount of memory was less than I had requested, > and so it smashed everything. That is a known issue with alloca, so it shouldn't be used with big amounts of memory (it creates objects on stack, so stack overflow can be reached easily). But, well, creating a really big array would do the same. Also, deep recursion will also smash the stack. So we don't have a deal like "remove alloca and your stack will be safe". But still, it's obsolete and compiler dependent. I'd better not stick to it. -- Cheers~ PGP key fingerprint: 07B3 2177 3E27 BF41 DC65 CC95 BDA8 88F1 E9F9 CEEF You can retrieve my public key at pgp.mit.edu.
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