Re: [Chicken-users] busy-wait in tcp-connect

[Kon Lovett]

On May 22, 2007, at 11:11 PM, felix winkelmann wrote:

> On 5/22/07, Dan Muresan <address@hidden> wrote:
> > >> While we're on the topic, I find Chicken's lightweight-threads and
> > >> srfi-18 compatible streams incredibly useful. However, it's a  
> > pity that
> > >> only unit tcp (and the (process) function) can create such  
> > streams.
> > >
> > > I assume you mean streams that block the current thread on I/O,  
> > yes?
> > > That shouldn't be a problem as long as you have an fd and can  
> > make it
> > > non-blocking.
> >
> > Yes, streams that block the current thread on I/O. Are you saying  
> > that I
> > can already create such streams from an fd? How?
>
> Kon has recently added ##sys#custom-[input|output]-port to the
> posix unix which sound like they are useful (Kon, can you say
> something about these?)

Not so recent ;-)

They are used by the '##sys#process' routine, which is the guts of  
the 'process' routines. Part of my refactoring of process into  
smaller pieces. The ##sys#custom-[input|output]-port routines are  
essentially the port creation code of the original 'process' procedure.

Im afraid they are undocumented for a reason:

- No UTF8 support
- No Read-String/Read-Line
- No Windows support

However, they do work (in use by the osprocess egg).

(##sys#custom-input-port LOCATION NAME FILENO
                         [BUFFER-INFO [ON-CLOSE [MORE-PREDICATE]]])

(##sys#custom-output-port LOCATION NAME FILENO
                          [BUFFER-INFO [ON-CLOSE]])

LOCATION        calling procedure/context id
NAME            name for the port (usually the process command pathname)
FILENO          open file descriptor
BUFFER-INFO     either a fixnum size or a string
ON-CLOSE        fileno was closed notification procedure
MORE-PREDICATE  boolean procedure indicating whether more input is  
available,
                usually not needed but the programmer may know  
something that
                the C 'read' procedure doesn't

Use (##sys#file-nonblocking! FILENO) before calling ##sys#custom- 
[input|output]-port if such is desired.

Best Wishes,
Kon

> You can also look at the nbstdin egg, which has a "nonblocking- 
> input-port"
> procedure.
>
>
> cheers,
> felix
>
>
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