Invalid connection after closing?
Thx for the information. I read it, but I wasn't sure what was going on inside. Is there a way to close a connection without destroying it? Guess not, but you never know... Cheers Joris
On Fri, Apr 8, 2011 at 5:09 PM, Duncan Murdoch <murdoch.duncan at gmail.com> wrote:
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
Joris Meys Statistical consultant Ghent University Faculty of Bioscience Engineering Department of Applied mathematics, biometrics and process control tel : +32 9 264 59 87 Joris.Meys at Ugent.be ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php