Nmap: Network Exploration and Security Auditing Cookbook - Second Edition

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Lua provides an interesting feature named coroutines. Each coroutine has its own execution stack. The most important part is that we can suspend and resume the execution via coroutine.resume() and coroutine.yield(). The function stdnse.base() was introduced to help identify if the main script thread is still running. It returns the base coroutine of the running script.

You can learn more about coroutines from Lua's official documentation:

• http://lua-users.org/wiki/CoroutinesTutorial
• http://www.lua.org/pil/9.1.html

For more information about debugging NSE script execution, go to Appendix C, NSE Debugging .