R help - Jan 2008 - Communicating with R through a named pipe: display refresh problem

Hello,

On a linux system I'm trying to send commands to R through a named pipe and
am *nearly* successful.  I can send R commands and can plot graphs.  The only
problem I have is getting the x11 display to refresh - it appears to hang
because of the pipe.

The R server:
$ mkfifo R_pipe
$ R --no-save < R_pipe

The R client:
$ cat>> R_pipe

Now, I can send R commands down the pipe:

Client side:
x <- seq(1,10)
x

Server side:
> x <- seq(1:10)
> x
 [1]  1  2  3  4  5  6  7  8  9 10

This is perfect.

Now if I try to create a plot, e.g. plot(1:100), the server
shows
> plot(1:100)
and the plot appears.  However, if a window briefly obscures the graphical
output, the x11 device won't refresh the display.  It would appear the pipe
is blocking the refresh.

Can anyone else confirm this happens and any suggestions how to get the display
to refresh?

Thanks in advance,
PJ

Rather, non-interactive R does not run an event loop.  The usual way 
around this is to use a pty, as R run from a pty is considered to be 
interactive.

(Whether a fifo and a named pipe are the same concept is moot: some OSes 
have one and not the other.)

The plan is to use threads in due course to handle X11 events.

On Tue, 22 Jan 2008, Parker Jones wrote:
>
> Hello,
>
> On a linux system I'm trying to send commands to R through a named pipe
and am *nearly* successful.  I can send R commands and can plot graphs.  The
only problem I have is getting the x11 display to refresh - it appears to hang
because of the pipe.
>
> The R server:
> $ mkfifo R_pipe
> $ R --no-save < R_pipe
>
> The R client:
> $ cat>> R_pipe
>
> Now, I can send R commands down the pipe:
>
> Client side:
> x <- seq(1,10)
> x
>
> Server side:
>> x <- seq(1:10)
>> x
> [1]  1  2  3  4  5  6  7  8  9 10
>
> This is perfect.
>
> Now if I try to create a plot, e.g. plot(1:100), the server shows
>> plot(1:100)
> and the plot appears.  However, if a window briefly obscures the graphical
output, the x11 device won't refresh the display.  It would appear the pipe
is blocking the refresh.
>
> Can anyone else confirm this happens and any suggestions how to get the
display to refresh?
>
> Thanks in advance,
> PJ
-- 
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 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595