Gabor,
You can grab the connection and destroy it via getConnection and then a
standard close call. (it actually lists that it is "closed" already, but
still in the set of existing connections. I can't speak to that difference).
> tryCatch(
+ readLines(tempfile(), warn = FALSE)[1],
+ error = function(e) NA,
+ warning = function(w) NA
+ )
[1] NA
> rm(list=ls(all.names = TRUE))
> gc()
used (Mb) gc trigger (Mb) max used (Mb)
Ncells 257895 13.8 592000 31.7 416371 22.3
Vcells 536411 4.1 8388608 64.0 1795667 13.7
>
> showConnections(all = TRUE)
description
0 "stdin"
1 "stdout"
2 "stderr"
3
"/var/folders/79/l_n_5qr152d2d9d9xs0591lh0000gn/T//RtmpZRcxmh/file128a13bffc77"
class mode text isopen can read can write
0 "terminal" "r" "text" "opened" "yes" "no"
1 "terminal" "w" "text" "opened" "no" "yes"
2 "terminal" "w" "text" "opened" "no" "yes"
3 "file" "r" "text" "closed" "yes" "yes"
> con = getConnection(3)
> con
A connection with
description
"/var/folders/79/l_n_5qr152d2d9d9xs0591lh0000gn/T//RtmpZRcxmh/file128a13bffc77"
class "file"
mode "r"
text "text"
opened "closed"
can read "yes"
can write "yes"
> close(con)
> showConnections(all=TRUE)
description class mode text isopen can read can write
0 "stdin" "terminal" "r" "text" "opened" "yes" "no"
1 "stdout" "terminal" "w" "text" "opened" "no" "yes"
2 "stderr" "terminal" "w" "text" "opened" "no" "yes"
HTH,
~G
On Thu, Dec 14, 2017 at 10:02 AM, Gábor Csárdi <csardi.ga...@gmail.com>
wrote:
> Consider this code. This is R 3.4.2, but based on a quick look at the
> NEWS, this has not been fixed.
>
> tryCatch(
> readLines(tempfile(), warn = FALSE)[1],
> error = function(e) NA,
> warning = function(w) NA
> )
>
> rm(list=ls(all.names = TRUE))
> gc()
>
> showConnections(all = TRUE)
>
> If you run it, you'll get a connection you cannot close(), i.e. the
> last showConnections() call prints:
>
> ❯ showConnections(all = TRUE)
> description
> 0 "stdin"
> 1 "stdout"
> 2 "stderr"
> 3 "/var/folders/59/0gkmw1yj2w7bf2dfc3jznv5w0000gn/T//Rtmpc7JqVS/
> filecc2044b2ccec"
> class mode text isopen can read can write
> 0 "terminal" "r" "text" "opened" "yes" "no"
> 1 "terminal" "w" "text" "opened" "no" "yes"
> 2 "terminal" "w" "text" "opened" "no" "yes"
> 3 "file" "r" "text" "closed" "yes" "yes"
>
> AFAICT, readLines should close the connection:
>
> ❯ readLines
> function (con = stdin(), n = -1L, ok = TRUE, warn = TRUE, encoding =
> "unknown",
> skipNul = FALSE)
> {
> if (is.character(con)) {
> con <- file(con, "r")
> on.exit(close(con))
> }
> .Internal(readLines(con, n, ok, warn, encoding, skipNul))
> }
> <environment: namespace:base>
>
> so maybe this just a symptom of an on.exit() issue?
>
> Or am I missing something and it is possible to close the connection?
>
> Thanks,
> Gabor
>
> ______________________________________________
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
--
Gabriel Becker, PhD
Scientist (Bioinformatics)
Genentech Research
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