[Rd] problems with connections when applied in tryCatch

Joris Meys jorismeys at gmail.com
Thu Aug 18 17:53:42 CEST 2011

Recently on stackoverflow following problem came up :


A reproducible example: When trying


No connections are shown, but after a number of calls, suddenly the message

Error in file(file, "rt") : all connections are in use

pops up. Trying to get them deleted with closeAllConnections() causes
R to crash on Windows 7. Another user reported a segfault. (see the
link to stackoverflow)

Although I initially thought on.exit() was somehow skipped, that's not
the case. In fact, the connection couldn't be opened, so it can't be
closed either. I have no clue as to why this goes wrong, but it shows
there's something odd happening with the connections. For the record,
I am aware that the use of the warning handler in that call is rather
peculiar. But even then, R shouldn't crash.


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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