[Rd] 1.8.0 on Unix: interrupting huge print()s ??

[Luke Tierney]

Needs a call to R_CheckUserInterrupt at the appropriate place.  The
only platform that currently can interrupt a long print seems to be
Rgui on Windows because of an event poll in the console output
function.  One possibility is to put in a check every 100 calls, say,
to Rvprintf in printutils.c.  I'll check that out and commit to the
patches branch unless anyone sees a problem or a better place to
check.

luke

On Fri, 10 Oct 2003, Martin Maechler wrote:

> NEWS for R 1.8.0 has
> 
> >>  USER-VISIBLE CHANGES
> >> 
> >>      <......>
> >> 
> >>      o	On Unix-like systems interrupt signals now set a flag that is
> >> 	 checked periodically rather than calling longjmp from the
> >> 	 signal handler.	 This is analogous to the behavior on Windows.
> >> 	 This reduces responsiveness to interrupts but prevents bugs
> >> 	 caused by interrupting computations in a way that leaves the
> >> 	 system in an inconsistent state.  It also reduces the number
> >> 	 of system calls, which can speed up computations on some
> >> 	 platforms and make R more usable with systems like Mosix.
> 
> and this has already caused grief here
> (actually it has several days ago, when I switched our users to
>  R-1.8.0beta  __ BUT THEY DIDN'T TELL ANY R DEVELOPER __ )
> 
> for a user who does use *large* matrices.
> 
> When accidentally calling print() {implicitly}, we have been
> used here to press CTRL+c (twice in Emacs ESS!) for stopping the
> output.
> 
> This no longer works in R 1.8.0 at least on our unix platforms.
> To reproduce, type
> 
>   cbind(1:1e6)
> 
> and try to cut it short (it only takes a minute or so,
> whereas our user here had a matrix that needed more than 10
> minutes of screen output !)
> 
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> 

-- 
Luke Tierney
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
   Actuarial Science
241 Schaeffer Hall                  email:      luke at stat.uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu