title: gdb core dump "is not a core dump: File format not recognized"
body: <p>I compiled my C file <code>test</code> with the flags <code>-g -Wall -std=gnu99 -pedantic</code></p>
  
  <p>I ran it and a <code>core</code> file was created</p>
  
  <p>I tried analysing it <code>gdb test core</code> and I get this error message</p>
  
  <pre><code>GNU gdb (Debian 7.12-6) 7.12.0.20161007-git
  Copyright (C) 2016 Free Software Foundation, Inc.
  License GPLv3+: GNU GPL version 3 or later &lt;http://gnu.org/licenses/gpl.html&gt;
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  This GDB was configured as "x86_64-linux-gnu".
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  &lt;http://www.gnu.org/software/gdb/bugs/&gt;.
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  Reading symbols from test...done.
  "/[...]/aula02/core" is not a core dump: File format not recognized
  </code></pre>