Invalid connection after closing?

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?
Cheers
Joris

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
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