Re: port initialization?

[Marius Vollmer <mvo@zagadka.ping.de>]

Han-Wen Nienhuys <hanwen@cs.uu.nl> writes:

> marius.vollmer@uni-dortmund.de writes:
> >>   z = scm_cell (scm_tc16_strport, 0);
> >> This looks like fishy code to me. When scm_add_to_port_table triggers
> >> GC then it will see the (scm_tc16_strport, 0) cell, which is (or
> >> should be) invalid.
> >
> >Yes, but the GC will not notice since "z" still refers to it and
> >therefore the port cell wont be freedo
> 
> That's not what I meant: z is a heap cell containing a null
> pointer. GC-ing it will dump core.

Sure?  Closed ports do contain NULL pointers as well and the GC can
handle them just fine.  The second word of a cell that is tagged as a
port is not a SCM.  The GC knows that and will not try to follow it
(except when freeing a port cell but then only when it is not flagged
as closed).  Am I missing somthing?

> > > 	SCM port = scm_cell (scm_tc16_port, newport);
> > > 	newport->port = port;
> > > 		      ..
> > >     }
> > /
> > This will leak newport when the call to scm_cell throws.
> 
> scm_cell throws, what do you mean?

I meant, when we run out of memory.  Does scm_cell signal an error
then (als scm_misc_error), or does it just abort the process?

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