Re: [Rd] Invalid connection after closing?

From: Duncan Murdoch <murdoch.duncan_at_gmail.com>
Date: Fri, 08 Apr 2011 11:09:30 -0400

On 08/04/2011 10:56 AM, Joris Meys wrote:
> Dear all,
>
> I do not completely understand following behaviour :
>
> > con<- file("test.txt")
> > isOpen(con)
> [1] FALSE
> > open(con)
> > isOpen(con)
> [1] TRUE
> > close(con)
> > isOpen(con)
> Error in isOpen(con) : invalid connection
> > str(con)
> Classes 'file', 'connection' atomic [1:1] 3
> ..- attr(*, "conn_id")=<externalptr>
>
> Why do I get an error, indicating an invalid connection, after I
> closed a connection? Is this to be expected?

Quoting ?close: " ‘close’ closes and destroys a connection. " In the current implementation, connections are a finite resource, and you need to be able to get rid of them when you are done. close(con) is the way to do that. If you want to re-open it, you need to remember the filename (or extract it before calling close()), and issue another call to file().

Duncan Murdoch



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