title: Finding entry points to Lua program from inside Lua enivronment
body: <p>I have a Lua runtime environment exposed through an API to a larger C system.  There are multiple entry points into the Lua program that are event driven by the C system.  There are also callbacks that I can make into the C system from inside Lua.  I have root access to the system running Lua but don't have the C source code.</p>
  
  <p>I've discovered the list of valid callbacks I can make to the C function from inside Lua as this is exposed internally - Lua has to know that these are valid functions.</p>
  
  <p>Is there any way of discovering the Lua functions that the C system will call? The API I'm using is not thoroughly documented and I'd like to know the list of Lua functions I can write that will be called by the C system.</p>