I'm trying to write a simple Lua script, and the time function is giving me a “loading module” error

Question

I'm trying to learn Lua, and the tutorial I'm following has the following code as a step:

 print("Welcome to")
 print("THE GAME")

I, having some prior experience programming, decided to take it a step further:

 require "socket"

 function sleep(sec)
     socket.select(nil, nil, sec)
 end

 print("Welcome to.....")
 sleep(1.25)
 print("...")
 sleep(1.25)
 print("...")
 sleep(1.25)
 print("...")
 sleep(1.25)
 print("...")
 sleep(1.25)
 print("THE GAME")

And for some reason, this small addition immediately gave me an error:

  dave@dave-[my laptop]:~/Code/Lua/Test$ lua main.lua
  lua: error loading module 'socket.core' from file '/home/dave/torch/install/lib/lua/5.1/socket/core.so':
     /home/dave/torch/install/lib/lua/5.1/socket/core.so: undefined symbol: lua_pcall
  stack traceback:
     [C]: in ?
     [C]: in function 'require'
     /home/dave/torch/install/share/lua/5.1/socket.lua:12: in main chunk
     [C]: in function 'require'
     main.lua:1: in main chunk
     [C]: in ?

I'm not sure how I broke something this simple. Did I install Lua wrong? I'm running Lua 5.2.3 on Ubuntu 14.04.

Answer 1

lib/lua/5.1/socket/core.so

I'm running Lua 5.2.3

Well, there's your problem. Lua is not binary compatible with previous "minor" versions. So you cannot load a .so that was built for Lua 5.1 when you're executing in Lua 5.2.

Assuming the socket library has a 5.2 version, you need to upgrade to it. If you can't do that, then you need to downgrade to Lua 5.1.