title: Under what circumstances can malloc return NULL?
body: <p>It has never happened to me, and I've programming for years now.</p>
  
  <p>Can someone give me an example of a non-trivial program in which <code>malloc</code> will actually not work? </p>
  
  <p><em>I'm not talking about memory exhaustion</em>: I'm looking for the simple case when you are allocating just one memory block in a bound size given by the user, lets say an integer, causes <code>malloc</code> to fail.</p>