Re: Strategies for Lua coroutines in C programs?

[Thomas Jericke <tjericke@...>]

On 04/10/2015 08:18 AM, Marc Balmer wrote:
> In an application that is written in C I am already using Lua for
> scripting, now I want to perform certain task in parallel to the main
> function (a cash register), e.g. handling certain credit card
> transactions in the background.
>
> My first approach was to create the coroutines using lua_newthread() and
> keep a list of runnable coroutines.  Then in the main event loop (it's
> an X11 application), when there are no X events to process, I would
> check if there are runnable coroutines and resume them, if there are.
> This immediately led to my application using 100% CPU time ( because
> it's constantly calling into Lua).
>
> My second approach, which seems to work well for now, was to return a
> number in coroutine.yield(), which is interpreted by the C program as a
> interval value in milliseconds.  The C program would then create an
> XtInterval and schedule the coroutine to be resumed in the specified
> time.  This way a coroutine schedules itself.
>
> What other strategies are being used?  How do others handle coroutines
> in hosted programs?
I also use your second approach. A coroutine may use 100% CPU if it 
wants to,
other wise it can also tell my scheduler to pause the coroutine for a 
certain time.
But I don't use the parameter of yield but instead I use a separate Lua 
function written in C
called "Sleep(...)". This sleep function first tells the scheduler how 
long the coroutine wants
to sleep and then calles yield. This way I am still able to use the 
parameter of yield for something else.

Also I think it makes the code more self explaining.
--
Thomas