title: What are the common undefined/unspecified behavior for C that you run into?
body: <p>An example of unspecified behavior in the C language is the order of evaluation of arguments to a function.  It might be left to right or right to left, you just don't know. This would affect how <code>foo(c++, c)</code> or <code>foo(++c, c)</code> gets evaluated.</p>
  
  <p>What other unspecified behavior is there that can surprise the unaware programmer?</p>