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Date: Fri, 09 Dec 2011 09:55:18 -0500
From: Ryan Johnson <ryan DOT johnson AT cs DOT utoronto DOT ca>
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To: cygwin AT cygwin DOT com
Subject: Re: gcc-4.5.3 segfaults wrt alloca
References: <20111209105801 DOT GA10388 AT po8371>
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On 09/12/2011 5:58 AM, Denis Excoffier wrote:
> I use the latest packages and cygwin snapshots. The problem described
> below began several snapshots in the past, around beginning of December.
>
> The following program, with static allocation of a reasonable amount
> of data, segfaults, maybe in alloca(). With a smaller size
> (eg 10000) it's ok. With new/malloc (even with 100 times more) it's
> ok. With C or C++. 100% reproducible.
>    unsigned int const SIZE = 689471;
>    int foo[SIZE];
Reasonable? You're trying to stack-allocate 2.5MB of data. Don't do that 
-- stack sizes are 2MB or less in most operating systems. Besides, doing 
anything useful with a buffer that size would completely drown out the 
overhead of calling malloc.

Ryan




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