[Rd] on.exit(par(old.par)) warnings

[Prof Brian Ripley]

>From the help page's examples section

     ## Alternatively,
     op <- par(no.readonly = TRUE) # the whole list of settable par's.
     ## do lots of plotting and par(.) calls, then reset:
     par(op)

and no, it's not new and it is not a mistake (in R).

On Mon, 12 May 2003, Paul Gilbert wrote:

> I often use something like
> 
>   old.par <- par(set someting)
>   on.exit(par(old.par))
> 
> but in R 1.7.0. I now get warnings:               

Note: that's not the same thing as the previous usage.

> > old.par <- par()
> > par(old.par)
> Warning messages: 
> 1: parameter "cin" can't be set in: par(args) 
> 2: parameter "cra" can't be set in: par(args) 
> 3: parameter "csi" can't be set in: par(args) 
> 4: parameter "cxy" can't be set in: par(args) 
> 5: parameter "din" can't be set in: par(args) 
> 6: gamma cannot be modified on this device in: par(args) 
> 
> Is this a mistake or a new feature? If it is a new feature, is there a simple
> way to avoid the warnings?

-- 
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)
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