Re: Thread in library which call Lua function

[jseb <gmane2010@...>]

>    It could be a threading issue.  For a quick test, edit llimits.h and
> comment out the defines for lua_lock() and lua_unlock().   Then provide a

Ok, i did so. the assert in "lua_lock" arise, so it's a threading problem.

So this method is not good:

[lua] require library from lua.
[lua] init library thread from lua.
[dll] get the name of the lua's callback in the registry, store it and
      store lua context.
[lua] enter in loop, and go out after n seconds.
[dll] while lua is waiting, the thread launched in dll call lua's
      callback when needed.

The problem is, Lua is not re-entrant (i know.. several people here said 
that to me). So Lua is called when it's in his lock state, and boom.

Better way shall be:

[dll] init lua state (luaL_newstate)
[dll] launch thread
[dll] when needed, call lua function from within the thread
[lua] (i'm called from inside dll)
      (all Lua's variables are stored in the lua state of the dll)


I tried this, because i use a method similar to my first attempt with 
freeglut.
Freeglut is initialised, and define its redraw callback like a calling 
to Lua. So the Freeglut loop is like this:

(sleep n ms) -> call redraw -> call lua function -> rearm freeglut timer
   ^                                                         |
   |_________________________________________________________|


I've got Freeglut sources, and searched for threads inside. No threads, 
as far i know. I don't know how Freeglut runs in parallel of my other 
code then (as he's sleeping most of time, it should block the other 
parts of my program if it wasn't threaded, but it doesn't).
So that's why i can store a Lua's context and its callback redraw 
function when using Freeglut. I was wrong trying to mimic this mechanism 
with threads.


Thanks to all who answered me, i've learned new things :)