[R] tempfile problem

[Ben Madin]

G'day all,

The documentation for tempfile states :

"The names are very likely to be unique among calls to tempfile in an R session and across simultaneous R sessions. The filenames are guaranteed not to be currently in use."

My problem I think relates to the second part of the sentence, which is the guarantee... and it is being met ... but I need to save the files as .png files, in the same directory, so I am adding the suffix and I suppose therefore the next offering can be unique (as it doesn't have the prefix)

I am using a command like :

> fname <- basename(tempfile("nahis", "/Library/WebServer/Documents/nahis/tmp"))

 on a mac, or 

> fname <- basename(tempfile("nahis", "/htdocs/nahis/tmp"))

on a FreeBSD system, as I need to be able to find the file from the web browser up to 24 hours later.

and then 

> this_filename <- paste(fname, ".png", sep = "")

and saving the file as this_filename, hence the next call doesn't find it's own suggestion, and starts again.

Is there any alternative filenameing approach I can use to get around this? Do I need to manually scan and reject the name if it matches the names I already have? Should I just digest the current time ? (It's working so far!)

cheers

Ben