OpenEuphoria

Re: Win32LIB dreams

• Posted by Kat <gertie at PELL.NET> Oct 20, 2000
• 506 views

On 20 Oct 2000, at 11:14, Derek Parnell wrote:

> Hi Ian,
>
>
> >What i would really like to see for Win32Lib is the ability to write call
> >backs for background processing... if that is at all possible, i find that
> >the timer is a little too slow even at 1 ms, and using a call back routine
> >for a thread is not at all safe, and you can't suspend or resume it without
> >crashing. So where i stand, background processing is the last place to go.
>
> >Ps, if it is already possible please inform me on how it is done!
>
> Can you exapnd on this a little.
>
> Are you talking about Windows calling a user-defined Euphoria routine? If
> so, have you read up about Euphoria's call_back function?
>
> --------------------------
> call_back
> Platform: WIN32, Linux
> Syntax: include dll.e
> a = call_back(i)
> Description: Get a machine address for the Euphoria routine with routine id
> i. This address can be used by Windows, or an external C routine in a
> Windows .dll, or Linux shared library (.so), as a 32-bit "call-back" address
> for calling your Euphoria routine.

So..... what happens if you have two Eu programs,

prog1.ew
 procedure a
  gets(1,b_callback)
   --- code using b_callback
 end procedure
a_callback = routine_id(procedure a)
puts(1,a_callback)
-- end program

prog2.ew
 procedure b
  gets(1,a_callback)
 --- code using a_callback
 end procedure
b_callback = routine_id(procedure b)
puts(1,b_callback)
-- end program

I can think of several ways to transfer all the routine_ids between any number
of
running programs, i used gets() cause it gets(the point across). This
two-program
approach naturally holds two running interpreters in memory, but that's why it
is
multitasking. You cannot expect any global vars will be shared, but transfering
them or
redeclaring constants in each program should be easy enough. If windoze pages
the
applications out to the disk swap file, something may crash, but if that is the
case,
lock the memory the procedures are using.

Kat,
wishing she had time to try this herself.