From ligges at statistik.tu-dortmund.de  Mon Aug 22 19:49:41 2011
From: ligges at statistik.tu-dortmund.de (Uwe Ligges)
Date: Mon, 22 Aug 2011 19:49:41 +0200
Subject: [Rd] problems with connections when applied in tryCatch
In-Reply-To: <CAO1zAVaQ=uZnp0YZpintN-1XeC+qE3Mqg596fPphnUrVM9FLjg@mail.gmail.com>
References: <CAO1zAVaQ=uZnp0YZpintN-1XeC+qE3Mqg596fPphnUrVM9FLjg@mail.gmail.com>
Message-ID: <4E5296B5.6040303@statistik.tu-dortmund.de>



On 18.08.2011 17:53, Joris Meys wrote:
> Recently on stackoverflow following problem came up :
>
> http://stackoverflow.com/questions/7103429/all-the-connections-are-in-use-execution-halted/7108799#7108799
>
> A reproducible example: When trying
>
> replicate(200,tryCatch(read.table("this.is.no.file"),
>            warning=function(w){print(showConnections());print("warning")}))
>
> 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.

Right, and not trivial to track down! At least I can reproduce it with 
R-devel under Windows Server 2008. Can you please file a bug report so 
it won't be forgotten.

Thanks,
Uwe Ligges



> Cheers
> Joris
>
>



[Rd] problems with connections when applied in tryCatch
Uwe Ligges