From kasperdanielhansen at gmail.com  Sat Aug 15 02:52:17 2015
From: kasperdanielhansen at gmail.com (Kasper Daniel Hansen)
Date: Fri, 14 Aug 2015 20:52:17 -0400
Subject: [Rd] Why not pthreads on Windows in 'parallel' package?
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References: <CAFDcVCQO4b8ss08ZM_zXAp-4FAXL1dRj=9vRK6dB7hRSWivJGQ@mail.gmail.com>
Message-ID: <CAC2h7uuUmE0EzTeUcWfifgYuJv6tWXGoY-x1=1V9Rpm7b+ZGDw@mail.gmail.com>

mclapply uses fork which is different from pthreads.  As I understand it,
pthreads requires you to rewrite code, fork is a system call which takes
care of completely replicating the current state of the process.

Kasper

On Fri, Aug 14, 2015 at 5:00 PM, Henrik Bengtsson <henrik.bengtsson at ucsf.edu
> wrote:

> On Windows there are a few 'pthreads' implementation, e.g.
> pthreads-w32 and winpthreads
> [https://cran.r-project.org/doc/manuals/r-devel/R-exts.html#Using-pthreads
> ].
> We're thinking of giving them a try for the matrixStats package, and
> basic tests indicates it works, but since Windows pthreads are not
> used by core R (or?) I've got a little bit worried that we will face
> overwhelming problems.
>
> So, why are the above Windows implementations not used in the
> 'parallel' package in order to add multicore support for mclapply() on
> Windows?  Was it tried but found to be unreliable?  Was it that no one
> had the time to do it?  License issues?  Are there any pointers to old
> R-devel threads discussing this?
>
> Thanks
>
> Henrik
>
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[Rd] Why not pthreads on Windows in 'parallel' package?
Kasper Daniel Hansen