title: What does <value optimized out> mean in gdb?
body: <pre><code>(gdb) n
  134   a = b = c = 0xdeadbeef + ((uint32_t)length) + initval;
  (gdb) n
  (gdb) p a
  $30 = &lt;value optimized out&gt;
  (gdb) p b
  $31 = &lt;value optimized out&gt;
  (gdb) p c
  $32 = 3735928563
  </code></pre>
  
  <p>How can gdb optimize out my value??</p>