[Rd] Re: [R] Process to both write to and read from (pipe/fork)?

Jan T. Kim jtk at cmp.uea.ac.uk
Tue Feb 1 20:50:17 CET 2005

On Tue, Feb 01, 2005 at 01:44:37PM +0000, Prof Brian Ripley wrote:
> [Moved from R-help.]
> One reason you cannot easily do this with basic R functions is that it is 
> not portable.  E.g. pipes on Windows 98 do not work like that, and 
> system() on that OS has to work hard to do something similar.

Ok, thanks -- I really thought (and hoped) that I was just overlooking
something obvious.

I'm not fully convinced that the portability issues necessarily
preclude providing the fork / pipe facilities, as there already is some
differentiation present now, reflected by capabilities(). In fact,
when I saw that availability of fifos is reflected by capabilities(),
I thought that then, more basic pipes must also be accessible somehow
(and spent some effort investigating this idea).

> If we only had to consider standard Unices, pipe() would allow read-write 
> modes.  As it is, it is easy for you to write an OS-specific extension.

Well, that is probably reasonably easy, but (not the least due to that
fact) I'm still surprised that it has not been done already. I can hardly
imagine that I'm the first one to want to use some external utility from
an R program in this way.

So, what do you R-devel folks do in this case, and what would you

> BTW, please re-read the distinction between R-devel and R-help in the 
> posting guide: this (and most of your other recent postings) seem to me to 
> fall unambiguously within the specification for R-devel.

At the time of writing, I thought I was asking for help in using R...

Best regards, Jan
 +- Jan T. Kim -------------------------------------------------------+
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