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Re: Why is this outputting alternate blank lines?

Message-ID <dn3bid-ps2.ln1@wilbur.25thandClement.com> (permalink)
From <william@wilbur.25thandClement.com>
Subject Re: Why is this outputting alternate blank lines?
Newsgroups comp.lang.c
References (1 earlier) <o2r7cs$6l1$1@dont-email.me> <o2s0sb$tb$1@dont-email.me> <o2s1i8$3qt$1@dont-email.me> <ln4m26nv0o.fsf@kst-u.example.com> <lnr35amfmt.fsf@kst-u.example.com>
Date 2016-12-15 10:24 -0800

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Keith Thompson <kst-u@mib.org> wrote:
> Keith Thompson <kst-u@mib.org> writes:
>> Richard Heathfield <rjh@cpax.org.uk> writes:
>>> On 14/12/16 17:53, DFS wrote:
>> [...]
>>>> Any idea why it crashes above 1 million?
>>>
>>> Do you remember when I suggested checking the return value of malloc?
>>>
>>> I again suggest that you check the return value of malloc.
>>>
>>> The malloc function returns NULL when it fails to allocate memory. Since 
>>> you're not checking for this, if ever it /does/ return NULL you will be 
>>> scribbling all over memory you don't own, hence the segfault.
>>
>> On the other hand, on some systems malloc() generally doesn't report
>> failure; rather if you allocate too much memory, a crash occurs when you
>> try to access it.  (This is arguably non-conforming.)
> 
> Which is not to say you shouldn't check the value returned by malloc(),
> even on systems that behave this way.

malloc can and will fail on Linux even with overcommit enabled. Linux still
obeys process resource limits. Per-process limits are often set to infinity
by default, but not always. Some distributions will have finite defaults
especially for non-root, interactive sessions. And it's always smart to set
specially tailored limits for service daemons to prevent, e.g., DoS attacks
on the system. This is also why I never use swap space on my servers, Linux
or not.

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Thread

Why is this outputting alternate blank lines? DFS <nospam@dfs.com> - 2016-12-13 23:18 -0500
  Re: Why is this outputting alternate blank lines? Melzzzzz <mel@zzzzz.com> - 2016-12-14 05:30 +0100
  Re: Why is this outputting alternate blank lines? mark.bluemel@gmail.com - 2016-12-14 00:59 -0800
  Re: Why is this outputting alternate blank lines? Richard Heathfield <rjh@cpax.org.uk> - 2016-12-14 10:38 +0000
    Re: Why is this outputting alternate blank lines? DFS <nospam@dfs.com> - 2016-12-14 12:53 -0500
      Re: Why is this outputting alternate blank lines? Richard Heathfield <rjh@cpax.org.uk> - 2016-12-14 18:05 +0000
        Re: Why is this outputting alternate blank lines? Keith Thompson <kst-u@mib.org> - 2016-12-14 11:57 -0800
          Re: Why is this outputting alternate blank lines? Richard Heathfield <rjh@cpax.org.uk> - 2016-12-14 20:05 +0000
            Re: Why is this outputting alternate blank lines? "James R. Kuyper" <jameskuyper@verizon.net> - 2016-12-14 15:21 -0500
            Re: Why is this outputting alternate blank lines? Keith Thompson <kst-u@mib.org> - 2016-12-14 12:28 -0800
              Re: Why is this outputting alternate blank lines? supercat@casperkitty.com - 2016-12-14 13:09 -0800
              Re: Why is this outputting alternate blank lines? Jean-Marc Bourguet <jm@bourguet.org> - 2016-12-14 22:53 +0100
                Re: Why is this outputting alternate blank lines? <william@wilbur.25thandClement.com> - 2016-12-14 15:47 -0800
            Re: Why is this outputting alternate blank lines? Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-12-14 15:41 -0700
              Re: Why is this outputting alternate blank lines? Richard Heathfield <rjh@cpax.org.uk> - 2016-12-14 23:26 +0000
                Re: Why is this outputting alternate blank lines? Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-12-14 17:33 -0700
                Re: Why is this outputting alternate blank lines? Richard Heathfield <rjh@cpax.org.uk> - 2016-12-15 00:42 +0000
                Re: Why is this outputting alternate blank lines? supercat@casperkitty.com - 2016-12-14 17:05 -0800
                Re: Why is this outputting alternate blank lines? Richard Heathfield <rjh@cpax.org.uk> - 2016-12-15 08:21 +0000
                Re: Why is this outputting alternate blank lines? supercat@casperkitty.com - 2016-12-15 09:15 -0800
                Re: Why is this outputting alternate blank lines? Richard Heathfield <rjh@cpax.org.uk> - 2016-12-15 17:50 +0000
                Re: Why is this outputting alternate blank lines? supercat@casperkitty.com - 2016-12-15 12:15 -0800
                Re: Why is this outputting alternate blank lines? Richard Heathfield <rjh@cpax.org.uk> - 2016-12-15 20:37 +0000
                Re: Why is this outputting alternate blank lines? raltbos@xs4all.nl (Richard Bos) - 2016-12-15 20:08 +0000
                Re: Why is this outputting alternate blank lines? Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-12-14 20:40 -0700
                Re: Why is this outputting alternate blank lines? Richard Heathfield <rjh@cpax.org.uk> - 2016-12-15 08:36 +0000
                Re: Why is this outputting alternate blank lines? Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-12-15 17:43 -0700
                Re: Why is this outputting alternate blank lines? Richard Heathfield <rjh@cpax.org.uk> - 2016-12-16 01:05 +0000
                Re: Why is this outputting alternate blank lines? Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-12-15 18:34 -0700
                Re: Why is this outputting alternate blank lines? <william@wilbur.25thandClement.com> - 2016-12-15 10:14 -0800
                Re: Why is this outputting alternate blank lines? raltbos@xs4all.nl (Richard Bos) - 2016-12-15 20:15 +0000
            Re: Why is this outputting alternate blank lines? Tim Rentsch <txr@alumni.caltech.edu> - 2016-12-15 01:51 -0800
              Re: Why is this outputting alternate blank lines? asetofsymbols@gmail.com - 2016-12-15 06:09 -0800
                Re: Why is this outputting alternate blank lines? Tim Rentsch <txr@alumni.caltech.edu> - 2016-12-15 17:47 -0800
          Re: Why is this outputting alternate blank lines? Keith Thompson <kst-u@mib.org> - 2016-12-14 12:15 -0800
            Re: Why is this outputting alternate blank lines? <william@wilbur.25thandClement.com> - 2016-12-15 10:24 -0800
          Re: overcommit is the plague Noob <root@127.0.0.1> - 2016-12-17 01:17 +0100
      Re: Why is this outputting alternate blank lines? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-14 20:19 +0000
        Re: Why is this outputting alternate blank lines? DFS <nospam@dfs.com> - 2016-12-14 17:44 -0500
          Re: Why is this outputting alternate blank lines? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-15 00:21 +0000
            Re: Why is this outputting alternate blank lines? mark.bluemel@gmail.com - 2016-12-15 00:56 -0800
              Re: Why is this outputting alternate blank lines? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-15 22:08 +0000
      Re: Why is this outputting alternate blank lines? Geoff <geoff@invalid.invalid> - 2016-12-14 13:39 -0800
      Re: Why is this outputting alternate blank lines? Ike Naar <ike@iceland.freeshell.org> - 2016-12-16 07:12 +0000

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