[R] reading PID

[Prof Brian D Ripley]

On Wed, 23 May 2001 B.Rowlingson at lancaster.ac.uk wrote:

> Prof Brian Ripley wrote:
>
> > That's an OS-specific question, isn't it?  Let me guess, Linux.  There is
> > no specific way to get the pid within an R process (what could you do
> > with it?), but you can trivially dyn.load some code to tell you via a call
> > to getpid.

Let me point out that all of the below is at least as complicated as the
above.

>  On most modern Linux machines you could read in /proc/self/status and
> get the
> 'Pid:' entry. Lots of other useful stuff in there too. I haven't quite
> figured
> out how to read in the various bits neatly because of all the tab
> characters
> floating around.
>
>  And a warning - /proc/ stuff is really meant for human eyes and not for
> machines
> to parse and obtain info from. That's what system calls are for. The
> /proc format
> is liable to change.
>
>  Or you can get it by using system() to run a command and then the $PPID
> env
> var to get the parent pid:
>
> pid <- system("echo $PPID",intern=T)
>
> > Of course adding a Sys.getpid() function would be easy, but what use would
> > it be?
>
>  Several running R processes could write their output to unique files
> labelled
> by pid perhaps? Would be more meaningful names than the output of
> tempfile()...

???  R's tempfile can produce perfectly meaningful names.


-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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