From:	Hans-Bernhard Broeker <broeker AT physik DOT rwth-aachen DOT de>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Hunting Sigsev Errors
Date:	28 Mar 2001 15:42:46 GMT
Organization:	Aachen University of Technology (RWTH)
Lines:	24
Message-ID:	<99t0pm$k1n$1@nets3.rz.RWTH-Aachen.DE>
References:	<3ac02f4b$0$14446$272ea4a1 AT news DOT execpc DOT com> <Um7w6.1128$eX4 DOT 241968 AT typhoon DOT tampabay DOT rr DOT com> <l48w6.369$083 DOT 262866 AT typhoon DOT tampabay DOT rr DOT com>
NNTP-Posting-Host:	acp3bf.physik.rwth-aachen.de
X-Trace:	nets3.rz.RWTH-Aachen.DE 985794166 20535 137.226.32.75 (28 Mar 2001 15:42:46 GMT)
X-Complaints-To:	abuse AT rwth-aachen DOT de
NNTP-Posting-Date:	28 Mar 2001 15:42:46 GMT
Originator:	broeker@
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

Greg Donnells <gad AT donnesys DOT com> wrote:
> Well, I've discovered something interesting regarding SIGSEV errors and gcc
> (2.953). Consider the following code fragment:

[...]
> #define ARRAYMAX 1024
[...]
>      struct rec {
>           long index;
>           char fname[512];
>      } allrecs[ARRAYMAX];

This is, as you suspected, your problem. You've just allocated
ARRAYMAX times 516 bytes, or 516 KB of memory, on the stack. That's
more than the default size of the whole stack, and will, indeed, cause
a solid crash.

For such large memory blocks, you should never rely on the stack
(i.e. automatic variables) to contain them. Use heap storage instead,
i.e. malloc() and friends.

-- 
Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de)
Even if all the snow were burnt, ashes would remain.

- Raw text -