title: When should I explicitly specify a StructLayout?
body: <p>I'm fiddling with calling DLLs from C#, and came across the need to define my own structs. Lots of articles force a sequential layout for the struct with</p>
  
  <pre><code>[StructLayout(LayoutKind.Sequential)]
  struct Foo ...
  </code></pre>
  
  <p>So, I followed suite, and my programme worked. Now, when I took the line out, it still works. Why do I need it?</p>