Henrik,

It's entirely possible to do this but it has quite a number of implications.
Such as, you have to ensure that the message you're invoking does not return
outside the receiver's frame (e.g. through a non-local return). If it does
(or gets prematurely terminated from a debugger) you are in deep trouble. In
other words - don't even think about it unless you have 180% fool-proof
exception and unwind handling system. Then, there is also quite a bit of a
problem when you think about invoking multiple messages like this - if you
invoke message A in process A then message B in process B and then (after
the process switch) message A tries to return, you'd have to return through
the C stack frame of message B. Good luck :-)

Messy. That stuff's so messy. I thought about it when doing the FFI stuff
but the possible complications were just way to much for me...

  - Andreas

> -----Original Message-----
> From: Henrik Gedenryd [mailto:Henrik.Gedenryd at lucs.lu.se]
> Sent: Wednesday, November 01, 2000 1:38 AM
> To: squeak at cs.uiuc.edu
> Cc: recipient list not shown
> Subject: Re: [VM] Hooks from module into platform support code?
> 
> 
> Forgive me if I am overlooking something really obvious, but 
> while we're
> almost on the topic, what is it prevents one from doing 
> ordinary message
> sends from C code by having the equivalent of the exact bytecodes of a
> message send as a sequence of (Slang-generated) C code? This is what I
> thought that exception code was doing when it triggers a 
> method for block
> unwinding or something.
> 
> Is it something like the interpreter not being reentrant?
> 
> Henrik
> 
>