Re: [Chicken-users] a couple of questions about foreign functions

[Valentyn Kamyshenko]

On Jan 22, 2004, at 12:02 AM, Felix Winkelmann wrote:

> Am Wed, 21 Jan 2004 23:52:38 -0800 hat Valentyn Kamyshenko 
> <address@hidden> geschrieben:
>
> > > When this function returns, `buf' will point into a dead stack area,
> > > so the data is likely to be corrupted after the return.
> >
> > I suspected it!.
> >
> > What makes the following code correct, then (have found it in 
> > runtime.c):
> >
> > [...]
> >
> > it looks like the vector is created on the stack, and then 'returned' 
> > to the continuation...
>
> Indeed. But the invocation of the continuation (via `C_kontinue') does
> *never* return, the data will remain on the stack and be collected
> when a certain stack-limit is reached. C-code wrapped with 
> ##core#primitive
> invokes it's continuation (and thus the stack is not popped), but code
> wrapped with foreign-[callback-]lambda will return normally, in C 
> fashion.
finally, I got it.
I had an impression that foreign-lambda never returns (that is, that it 
behaves the same way as ##core#primitive). I'd suggest to add a line to 
the documentation that makes it clear.
Thank you!

Yet another question.
Do I understand correctly, that for proper signal handling (in unix) 
the main branch should explicitly pass control to the scheduler? That 
is, e.g., if I use a library that uses (blocking) select or accept, the 
signals will be queued until the select (or accept) returns?
Is there a workaround?

Thanks,

        Valentyn.