Re: Thread in library which call Lua function

["Robert G. Jakabosky" <bobby@...>]

On Saturday 16, jseb wrote:
> 
> 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).

Freeglut might be using alarm(2) and a signal handler on SIGALRM for the 
timer.

> 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.

Signals have the same thread-safety issues that threads do.  You can't safely 
call a Lua function from a signal handler.

-- 
Robert G. Jakabosky