similar to: isOpen on closed connections

On Thu, Dec 14, 2017 at 7:56 PM, Gabriel Becker <gmbecker at ucdavis.edu> wrote: > Gabor, > > You can grab the connection and destroy it via getConnection and then a > standard close call. Yeah, that's often a possible workaround, but since this connection was opened by readLines() internally, I don't necessarily know which one it is. E.g. I might open multiple

Thanks for tracking this down. Yeah, I should use suppressWarnings(), you are right. Although, readLines() might throw another warning, e.g. for incomplete last lines, and you don't necessarily want to suppress that. TBH I am not sure why that warning is given: ? con <- file(tempfile()) ? open(con) Error in open.connection(con) : cannot open the connection In addition: Warning message: In

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: ?

SUMMARY: I'm proposing that R assert that 'connection' options have not changed since first created such that R will produce the following error: > fh <- file("a.txt", open = "w+") > cat("hello\n", file = fh) > close(fh) > fh2 <- file("b.txt", open = "w+") > cat("world\n", file = fh2) >

Thought I'd try and start a discussion. Feel free to jump in. I guess R needs to strike the right balance between opening up the internals to package writers and not allowing them to do bad things. My first attempt at cracking this nut is to just memcpy() the Rconnection and not allow access to the private stuff: /* Alternative to allowing C code access to connection API. */ Rconnection

Hello, >From the doc, it says: "isOpen returns a logical value, whether the connection is currently open." But actually it seems to die on closed connections: > con <- file() > isOpen(con) [1] TRUE > close(con) > isOpen(con) Error in isOpen(con) : invalid connection Is it expected ? Tested on R-3.0.2 and R version 3.1.0 Patched (2014-06-11 r65921) on linux x86_64

On Thu, Dec 14, 2017 at 12:17 PM, G?bor Cs?rdi <csardi.gabor at gmail.com> wrote: > On Thu, Dec 14, 2017 at 7:56 PM, Gabriel Becker <gmbecker at ucdavis.edu> > wrote: > > Gabor, > > > > You can grab the connection and destroy it via getConnection and then a > > standard close call. > > Yeah, that's often a possible workaround, but since this

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 >

This has nothing to do with on.exit. It is an iteraction between where the warning is signaled in 'file' and your _exiting_ warning handler. This combination has the same issue, tryCatch(file(tempfile(), "r"), warning = identity) showConnections(all = TRUE) as does options(warn=2) file(tempfile(), "r") showConnections(all = TRUE) I haven't looked at the

Hi! I'm wondering if there's a smart way around this: fileName= (some valid file on your system) > fileCon=file(fileName, open="rt") > l<-readLines (fileCon, n= 1) > > isOpen(fileCon) [1] TRUE > close(fileCon) > isOpen(fileCon) Error in isOpen(fileCon) : invalid connection How do you test for a file being closed if isOpen gives you an error

This may be more of an OS question ... I have this call r = get.hist.quote(symbol, start= format(start, "%Y-%m-%d"), end= format(end, "%Y-%m-%d")) which does a url request in a loop and my program runs out of file handlers after few hundred rotations. The error message is: 'Too many open files'. Other than increasing the file handlers assigned to my process, is there

Hi all, I'm working on a function that reads online data that is only available to certain IPs. It then writes a subset of the data into a file. So whenever I'm logged in elsewhere or am not connected to the internet, I get an error, and the function is terminated. I want it to rather print a message into the file. Is there any way to test whether a connection can be opened? Analogous to

I was wondering if there was a function like "does connection exists" ? I am currently using loops to build up a database, and I have either > B = getConnection(localization) Error in getConnection(localization) : there is no connection -2147483648 In addition: Warning message: In getConnection(localization) : NAs introduced by coercion or > B = scan(localization) Error in

I noticed the following file descriptor leak when I couldn't remove a package unless I shut down the R session that had loaded and used it. The function that triggered the problem printed the output of a call to parse(). Each time one prints a srcref a connection is opened and not closed. It looks like it happens in as.character.srcref's call to getSrcLines, which has some logic I

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

When I originally implemented connections in R 1.2.0, I followed the model in the 'Green Book' closely. There were a number of features that forced a particular implementation, and one was getConnection() that allows one to recreate a connection object from a number. I am wondering if anyone makes use of this, and if so for what? It would seem closer to the R philosophy to have

I have been experiencing issues with an R script hanging when connecting to an Oracle database. To help debug, I found a function here in the nabble forum and made a small test script: #!/usr/bin/Rscript --no-restore --no-save --no-init-file library("RJDBC") drv<-JDBC("oracle.jdbc.OracleDriver","/home/oracle/lib/ojdbc6.jar", "'") dbCheck =

Hello, I have R as a socket server that computes R code sent by some scripts (the clients). These scrips send R code to generate models (SVM). The problem is that first models are generated in less than one second and one hour later, the same models are generated in more than ten seconds (even training with same data). If I restart the server , then it works well (fast). I don't know if I have

Using dup() before fdopen() (and calling fclose() on the connection when it is closed) indeed fixes the memory leak. FYI, Gabor Index: src/main/connections.c =================================================================== --- src/main/connections.c (revision 71653) +++ src/main/connections.c (working copy) @@ -576,7 +576,7 @@ fp = R_fopen(name, con->mode); } else { /* use

Hello R developers, I am working on the "seqinr" package and I encounter a tricky problem using a C function. We defined a C fonction called "getzlibsock" which is dedicated to compressed socket connections. This function is using the R internal C function called "getConnection(int)" in order to get information about the socket previously opened with the