Lua Quick Start Guide

Multiple hooks

Multiple hooks can be specified by adding a space and another letter to debug.sethook. For example, you could subscribe to every possible event, like so:

debug.sethook(trace, "l c r", 1)

When subscribing to multiple hooks, remember the callback's second argument is nil, except for the line event. Check for nil as appropriate. The following code demonstrates how to do this:

function trace(event, line)  local info = debug.getinfo(2)  if info.what == "Lua" then    print ("event: " .. event)    print (" function: " .. info.name)    print (" defined on: " .. info.linedefined)    if line ~= nil then      print (" called from: " .. line)    end  endend