[R] function in order to plot the same graph to postscript and pdf

[Ronny Klein]

Hi,

I've written a function in order to plot the same graph in a postcript and in 
a pdf file. Unfortunately, the second graph is always empty, i.e.:

plot.both <- function{myplot, filename}{
  pdf(file=paste(filename, ".pdf", sep=""))
   myplot
  dev.off()
  postscript(file=paste(filename, ".eps", sep=""))
   myplot
  dev.off()
}

yields in a correct pdf but an empty eps file. However something like this:

plot.both <- function{myplot1, myplot2, filename}{
  pdf(file=paste(filename, ".pdf", sep=""))
   myplot1
  dev.off()
  postscript(file=paste(filename, ".eps", sep=""))
   myplot2
  dev.off()
}

yields the expected results even if myplot1 and myplot2 are identical.

Does somebody know, how I can implement the desired (first) function?

Ronny

PS: My system is: Linux Debian Unstable and R-Version:  2.0.1.